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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2016	Mar. 01, 2017	Jun. 30, 2016
Document and Entity Information
Entity Registrant Name	COLLEGIUM PHARMACEUTICAL, INC
Entity Central Index Key	0001267565
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 197
Entity Common Stock, Shares Outstanding		29,448,609
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 153,225	$ 95,697
Accounts receivable, net	2,129
Inventory	1,316
Prepaid expenses and other current assets	1,905	1,186
Total current assets	158,575	96,883
Property and equipment, net	1,038	738
Intangible assets, net	2,103
Restricted cash	97	97
Other long-term assets	204
Total assets	162,017	97,718
Current liabilities:
Accounts payable	9,106	3,537
Accrued expenses	8,879	2,228
Deferred revenue	4,944
Current portion of term loan payable	2,667	2,667
Total current liabilities	25,596	8,432
Lease incentive obligation	34	68
Term loan payable, long-term	1,479	4,146
Total liabilities	27,109	12,646
Commitments and contingencies (see Note 9)
Shareholders’ equity (deficit):
Preferred stock, $0.001 par value; authorized shares - 5,000,000 at December 31, 2016 and December 31, 2015; issued and outstanding shares - none at December 31, 2016 and December 31, 2015
Common stock, $0.001 par value; authorized shares - 100,000,000 at December 31, 2016 and December 31, 2015; issued and outstanding shares - 29,364,100 at December 31, 2016 and 20,739,351 at December 31, 2015	29	21
Additional paid-in capital	358,063	214,062
Accumulated deficit	(223,184)	(129,008)
Treasury stock		(3)
Total shareholders’ equity	134,908	85,072
Total liabilities and shareholders’ equity	$ 162,017	$ 97,718

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, authorized shares	5,000,000	5,000,000
Preferred stock, issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	29,364,100	20,739,351
Common stock, outstanding shares	29,364,100	20,739,351

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Product revenues, net	$ 1,711
Costs and expenses
Cost of product revenues	213
Research and development	14,948	$ 7,975	$ 14,959
Selling, general and administrative	80,632	18,932	2,706
Total costs and expenses	95,793	26,907	17,665
Loss from operations	(94,082)	(26,907)	(17,665)
Other expense (income):
Interest expense, net	94	439	252
Gain on extinguishment of debt		(91)
Change in fair value of derivative liability			7
Total other expense, net	94	348	252
Net loss	$ (94,176)	$ (27,255)	$ (17,917)
Loss per share - basic and diluted	$ (3.88)	$ (1.48)	$ (22.72)
Weighted-average shares - basic and diluted	24,262,945	13,542,282	933,997

CONSOLIDATED STATEMENTS OF CONVERTIBLE REDEEMABLE PREFERRED STOCK AND SHAREHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Series A convertible redeemable preferred stock	Series B convertible redeemable preferred stock	Series C convertible redeemable preferred stock	Series D convertible redeemable preferred stock	Common Stock	Additional Paid-In Capital	Treasury Stock, at cost	Accumulated Deficit	Total
Balance at beginning of year at Dec. 31, 2013	$ 12,277	$ 49,376	$ 12,154		$ 1	$ 12,313	$ (3)	$ (80,536)
Balance at beginning of year at Dec. 31, 2013									$ (68,225)
Balance at beginning of year (in shares) at Dec. 31, 2013					962,960
Increase (decrease) in convertible redeemable preferred stock
Exercise of common stock options						72			72
Exercise of common stock options, shares					32,390
Issuance of restricted stock awards to employees, shares					10,869
Accruals of dividends and accretion to redemption value	504	1,836	960						3,300
Accruals of dividends and accretion to redemption value								(3,300)	(3,300)
Stock-based compensation expense						22			22
Net loss								(17,917)	(17,917)
Balance at end of year at Dec. 31, 2014	$ 12,781	$ 51,212	$ 13,114		$ 1	12,407	(3)	(101,753)
Balance at end of year at Dec. 31, 2014									(89,348)
Balance at end of year (in shares) at Dec. 31, 2014	9,232,334	27,324,237	8,658,008		1,006,219
Increase (decrease) in convertible redeemable preferred stock
Exercise of common stock options						517			517
Exercise of common stock options, shares					173,251
Issuance of restricted stock awards to employees, shares					194,694
Accruals of dividends and accretion to redemption value	$ 2,297	$ 18,034	$ 2,996	$ 1,245					24,572
Accruals of dividends and accretion to redemption value						(24,572)			(24,572)
Exercise of warrants						6			6
Exercise of warrants (in shares)					16,062
Issuance of convertible redeemable preferred stock, net of issuance costs				$ 44,807
Issuance of convertible redeemable preferred stock, net of issuance costs, shares				37,500,000
Conversion of notes to convertible redeemable preferred stock				$ 5,000
Conversion of notes to convertible redeemable preferred stock, shares				4,166,667
Extinguishment of prior preferred stock dividends	(3,733)	(23,341)	(4,110)
Extinguishment of prior preferred stock dividends						31,184			31,184
Conversion of preferred stock to common stock	$ (11,345)	$ (45,905)	$ (12,000)	$ (50,000)	$ 13	119,237			119,250
Conversion of preferred stock to common stock, shares	9,232,334	27,324,237	8,658,008	41,666,667	12,591,463
Public offering of common stock, net of issuance costs					$ 7	72,022			72,029
Public offering of common stock, net of issuance costs, shares					6,670,000
Issuance of common stock in payment of accrued dividends				$ (1,052)		1,052			1,052
Issuance of common stock in payment of accrued dividends, shares					87,662
Stock-based compensation expense						2,209			2,209
Net loss								(27,255)	(27,255)
Balance at end of year at Dec. 31, 2015					$ 21	214,062	(3)	(129,008)
Balance at end of year at Dec. 31, 2015									85,072
Balance at end of year (in shares) at Dec. 31, 2015					20,739,351
Increase (decrease) in convertible redeemable preferred stock
Exercise of common stock options						443			443
Exercise of common stock options, shares					81,831
Public offering of common stock, net of issuance costs					$ 8	137,332			137,340
Public offering of common stock, net of issuance costs, shares					8,500,000
Issuance for employee stock purchase plan						442			442
Issuance for employee stock purchase plan, shares					42,918
Retirement of treasury stock						(3)	$ 3
Stock-based compensation expense						5,787			5,787
Net loss								(94,176)	(94,176)
Balance at end of year at Dec. 31, 2016					$ 29	$ 358,063		$ (223,184)
Balance at end of year at Dec. 31, 2016									$ 134,908
Balance at end of year (in shares) at Dec. 31, 2016					29,364,100

CONSOLIDATED STATEMENTS OF CONVERTIBLE REDEEMABLE PREFERRED STOCK AND SHAREHOLDERS’ EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Sale of stock
Issuance costs	$ 845	$ 2,408
Series D convertible redeemable preferred stock
Sale of stock
Issuance costs		193
Issuance costs		$ 193

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net loss	$ (94,176)	$ (27,255)	$ (17,917)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	655	171	187
Lease incentive	(34)	(34)	(34)
Stock-based compensation expense	5,787	2,209	22
Non cash interest expense		6	7
Change in fair value of derivative liability			7
Changes in operating assets and liabilities:
Accounts receivable	(2,129)
Inventories	(1,316)
Prepaid expenses and other assets	(923)	(659)	183
Refundable PDUFA fee		2,335	(2,335)
Accounts payable	5,569	1,298	990
Accrued expenses	6,570	362	943
Deferred revenue	4,944
Net cash used in operating activities	(75,053)	(21,567)	(17,947)
Investing activities
Purchase of intangible assets	(2,500)
Purchases of property and equipment	(477)	(362)	(8)
Net cash used in investing activities	(2,977)	(362)	(8)
Financing activities
Proceeds from issuance of convertible bridge note			5,000
Proceeds from issuances of common stock from public offerings, net of issuance costs of $845 and $2,408	137,340	72,029
Proceeds from issuances of common stock from employee stock purchase plans	442
Proceeds from notes payable, net of original note payoff			7,056
Proceeds from issuance of Series D convertible redeemable preferred stock, net of issuance costs of $193		44,807
Repayment of term note	(2,667)	(1,286)	(28)
Repayment of lease note payable		(59)	(62)
Restricted cash		(16)
Proceeds from the exercise of stock options	443	517	72
Net cash provided by financing activities	135,558	115,992	12,038
Net increase (decrease) in cash and cash equivalents	57,528	94,063	(5,917)
Cash and cash equivalents at beginning of period	95,697	1,634	7,551
Cash and cash equivalents at end of period	153,225	95,697	1,634
Supplemental disclosure of cash flow information
Cash paid for interest	284	353	181
Supplemental disclosure of non-cash activities
Acquisition of property and equipment in accrued expenses	$ 81
Preferred stock conversion to common stock		120,302
Extinguishment of preferred stock		31,184
Accruals of dividends and accretion to redemption value		24,572	3,300
Conversion of bridge note to preferred stock		5,000
Repayment of term note with proceeds of notes payable			944
Series C convertible redeemable preferred stock
Supplemental disclosure of non-cash activities
Accruals of dividends and accretion to redemption value		2,996	$ 960
Series D convertible redeemable preferred stock
Supplemental disclosure of non-cash activities
Accruals of dividends and accretion to redemption value		$ 1,245

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Issuance costs	$ 845	$ 2,408
Series D convertible redeemable preferred stock
Class of Stock [Line Items]
Issuance costs		193
Initial public offering \| Common stock
Class of Stock [Line Items]
Issuance costs	$ 845	$ 2,408

NATURE OF BUSINESS	12 Months Ended
NATURE OF BUSINESS	Dec. 31, 2016
NATURE OF BUSINESS.
NATURE OF BUSINESS	1. NATURE OF BUSINESS Organization Collegium Pharmaceutical, Inc. (the “Company”) was incorporated in Delaware in April 2002 and then reincorporated in Virginia in July 2014. The Company has its principal operations in Canton, Massachusetts. The Company is a specialty pharmaceutical company developing and commercializing next-generation abuse-deterrent products that incorporate the Company’s patented DETERx® technology platform for the treatment of chronic pain and other diseases. The Company’s first product, Xtampza ER®, or Xtampza, is an abuse-deterrent, extended-release, oral formulation of oxycodone, a widely prescribed opioid medication. In April 2016, the U.S. Food and Drug Administration (“FDA”) approved the Company’s new drug application (“NDA”) filing for Xtampza for the management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate. In June 2016, the Company announced the commercial launch of Xtampza. The Company’s operations are subject to certain risks and uncertainties. The principal risks include inability to successfully commercialize products, changing market conditions for products and product candidates (including development of competing products), changing regulatory environment and reimbursement landscape, negative outcome of clinical trials, inability or delay in completing clinical trials or obtaining regulatory approvals, the need to retain key personnel and protect intellectual property, patent infringement litigation and the availability of additional capital financing on terms acceptable to the Company. Public Offerings of Common Stock In May 2015, the Company closed an initial public offering (“IPO”) of its common stock, which resulted in the sale of 6,670,000 shares of its common stock at a public offering price of $12.00 per share, including 870,000 shares of common stock upon the exercise by the underwriters of their option to purchase additional shares at the public offering price. The Company received proceeds from the IPO of approximately $72,029 after deducting underwriting discounts, commissions and expenses payable by the Company. In April 2015, in connection with preparing for the IPO, the Company’s board of directors and shareholders approved a one‑for‑6.9 reverse split of the Company’s common stock. All common stock share and per share amounts in the financial statements have been retroactively adjusted for all periods presented to give effect to the reverse split of the Company’s common stock, including reclassifying an amount equal to the reduction in par value to additional paid‑in capital. In connection with the closing of the IPO, all of the Company’s outstanding convertible preferred stock and accrued dividends automatically converted to common stock in May 2015, resulting in an additional 12,591,463 shares of common stock of the Company becoming outstanding. The significant increase in common stock outstanding in May 2015 impacted the year-over-year comparability of the Company’s net loss per share calculations. In January 2016, the Company issued and sold in a public offering an aggregate of 2,750,000 shares of its common stock at $20.00 per share. The Company received net proceeds from this public offering of approximately $51,174, after deduction of underwriting discounts and commissions and expenses payable by the Company. In October 2016, the Company issued and sold in a public offering an aggregate of 5,750,000 shares of its common stock at $16.00 per share. The Company received net proceeds from this public offering of approximately $86,166, after deduction of underwriting discounts and commissions and expenses payable by the Company. Basis of Accounting The consolidated financial statements include the accounts of Collegium Pharmaceutical, Inc. (a Virginia corporation) as well as the accounts of Collegium Securities Corp. (a Massachusetts corporation), incorporated in December 2015, a wholly-owned subsidiary requiring consolidation, and are prepared in conformity with accounting principles generally accepted in the United States of America. All intercompany balances and transactions have been eliminated in consolidation. Liquidity The Company has experienced net losses and negative cash flows from operating activities since its inception, and as of December 31, 2016 and December 31, 2015, had an accumulated deficit of $223,184 and $129,008, respectively. The Company expects to continue to incur net losses in the foreseeable future. A successful transition to profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. The Company believes that its cash and cash equivalents at December 31, 2016, together with expected cash inflows from the commercialization of Xtampza will enable the Company to fund its operating expenses, debt service and capital expenditure requirements into 2019. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional cash. Management intends to fund future operations through additional private or public debt or equity offerings, and may seek additional capital through arrangements with strategic partners or from other sources. If the Company is unable to obtain financing or increase profitability, the related lack of liquidity will have a material adverse effect on the Company’s operations and future prospects.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

12 Months Ended

Dec. 31, 2016

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Use of Estimates

The preparation of the Company’s financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. The most significant estimates in the Company’s financial statements relate to revenue recognition, including the estimates of units prescribed, discounts and allowances related to commercial sales of Xtampza, estimates utilized in the valuation of inventory, estimates of useful lives with respect to intangible assets, accounting for stock-based compensation, contingencies, intangible assets, tax valuation reserves and accrued expenses. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. The Company evaluates its estimates and assumptions on an ongoing basis. The Company’s actual results may differ from these estimates under different assumptions or conditions.

Fair Value Measurements

Disclosures of fair value information about financial instruments are required, whether or not recognized in the balance sheet, for financial instruments with respect to which it is practicable to estimate that value. The carrying amounts reported in the Company’s financial statements for cash and cash equivalents, accounts payable, term loan payable and accrued liabilities approximate their respective fair values because of the relative short‑term nature of these accounts.

Fair value measurements and disclosures describe the fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value, as follows:

Level 1: Quoted prices in (unadjusted) active markets for identical assets or liabilities

Level 2: Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly.

Level 3: Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability.

Transfers are calculated on values as of the transfer date. There were no transfers between Levels 1, 2 and 3 during the years ended December 31, 2016 and 2015.

The following tables present the Company’s financial instruments carried at fair value using the lowest level input applicable to each financial instrument at December 31, 2016 and 2015.


						Significant
				Quoted Prices		other		Significant
				in active		observable		unobservable
				markets		inputs		inputs
Description		Total		(Level 1)		(Level 2)		(Level 3)
December 31, 2016
Money market funds, included in cash equivalents	$	125,515	$	125,515	$	—	$	—

December 31, 2015
Money market funds, included in cash equivalents	$	94,912	$	94,912	$	—	$	—

Concentration of Credit Risk

Financial instruments, which potentially subject the Company to significant concentration of credit risk, consist primarily of cash and cash equivalents and accounts receivable. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. Three customers comprised 10% or more of the Company’s accounts receivable balance as of December 31, 2016. These customers comprised 44%, 27% and 21% of the accounts receivable balance, respectively. Three customers comprised 10% or more of the Company’s revenue during the year ended December 31, 2016. These customers comprised 35%, 28% and 27% of revenue, respectively. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the financial institutions in which those deposits are held. The Company has no financial instruments with off‑balance sheet risk of loss.

Cash and Cash Equivalents

Cash and cash equivalents include cash in readily available checking and savings accounts and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents.

The Company’s cash equivalents, which consist of money market funds, are measured at fair value on a recurring basis. As of December 31, 2016 and 2015, the carrying amount of cash equivalents was $125,515 and $94,912, respectively, which approximates fair value and was determined based upon Level 1 inputs. Money market funds are valued using quoted market prices with no valuation adjustments applied. Accordingly, these securities are categorized as Level 1.

Inventory

Inventories are stated at the lower of cost or net realizable value. Inventory costs consist of costs related to the manufacturing of Xtampza, which are primarily the costs of contract manufacturing. The Company determines the cost of its inventories on a specific identification basis, and removes amounts from inventories on a first-in, first-out basis. If the Company identifies excess, obsolete or unsalable items, inventories are written down to their realizable value in the period in which the impairment is identified. These adjustments are recorded based upon various factors, including the level of product manufactured by the Company, the level of product in the distribution channel, current and projected demand for the foreseeable future and the expected shelf-life of the inventory components. Estimates of excess inventory consider various factors, including inventory levels, the level of product in the distribution channel, the Company’s projected sales of the product, as well as the remaining shelf lives of the product. The Company recorded such adjustments of $100 in the year ended December 31, 2016, which were recorded as a component of cost of product revenues. Inventories that are not expected to be used within one year are recorded as a non-current asset.

The Company outsources the manufacturing of Xtampza to a sole contract manufacturer that produces the finished product. In addition, the Company currently relies on a sole supplier for the active pharmaceutical ingredient for Xtampza. Accordingly, the Company has concentration risk associated with its commercial manufacturing of Xtampza.

Prior to the approval of Xtampza by the FDA in April 2016, the Company recorded all costs incurred related to the manufacturing of Xtampza as research and development expense. Subsequent to approval, the Company began capitalizing these costs as inventory as they are incurred.

The Company has capitalized $1,316 of inventory as of December 31, 2016. The Company expects sales of the capitalized units to occur during the next twelve months. The Company expects costs of product revenues to increase due to the expected increases in net product sales of Xtampza and the fact that the Company had expensed all manufacturing costs as research and development expense in periods prior to FDA approval of Xtampza. The impact on cost of product revenues as a result of inventory not capitalized prior to FDA approval is immaterial.

Property and Equipment

Property and equipment are recorded at historical cost. Maintenance and repair costs are expensed as incurred. Costs which materially improve or extend the lives of existing assets are capitalized. The Company provides for depreciation and amortization using the straight‑line method over the estimated useful lives of the assets, which are as follows:


Asset Category	Estimated Useful Life
Machinery and equipment		5	years
Computers and office equipment		3 - 5	years
Furniture and fixtures		7	years
Leasehold improvements		Lesser of remaining lease term and estimated useful life

Upon retirement or sale, the cost of assets disposed and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is recorded in the statements of operations.

Intangible Assets

Intangible assets that are deemed to have a definite life are amortized over their useful lives and are evaluated separately for impairment at least annually or whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable (See Note 7). Amortization of intangible assets is recognized on a straight-line basis and the useful life of the Company’s only intangible asset is approximately 3.7 years.

Restricted Cash

Restricted cash represents cash held in a depository account at a financial institution to collateralize a conditional stand‑by letter of credit related to the Company’s Canton, Massachusetts facility lease agreement. Restricted cash is reported as non‑current unless the restrictions are expected to be released in the next twelve months.

Revenue Recognition

Revenue for product sales is recognized when there is persuasive evidence of an arrangement, title and risk of loss have passed to the customer, when estimated provisions for chargebacks, rebates, sales incentives and allowances, distribution service fees, and returns are reasonably determinable, and when collectability is reasonably assured. Product revenue is recorded net of estimated chargebacks, rebates, sales incentives and allowance, distribution service fees, as well as estimated product returns.

The Company sells Xtampza in the United States principally to distributors and retailers (“customers”), which in turn sell the product to healthcare providers for the treatment of patients. The Company provides the right of return to its customers for unopened product for a limited time before and after its expiration date. Given the Company’s limited sales history for Xtampza and the inherent uncertainties in estimating product returns, the Company has determined that the shipments of Xtampza made to its customers thus far do not meet the criteria for revenue recognition at the time of shipment. Accordingly, the Company recognizes revenue when the product is sold-through to patients, provided all other revenue recognition criteria are met. The Company invoices its customers upon shipment of Xtampza and records accounts receivable, with a corresponding liability for deferred revenue equal to the gross invoice price, less any realized adjustments to the gross invoice price. The Company then recognizes revenue when Xtampza is sold-through, or when product is prescribed directly to the patient at which time the right of return has expired. Healthcare providers to whom distributors sell Xtampza hold limited inventory that is designated for patients, thereby limiting the risk of return.

Research and Development Costs

Research and development costs are charged to expense as incurred and consist of costs incurred to further the Company’s research and development activities including salaries and employee related costs, costs associated with market research and design, costs associated with conducting preclinical, clinical and regulatory activities including fees paid to third‑party professional consultants and service providers, costs incurred under clinical trial agreements, costs for laboratory supplies and laboratory equipment, costs to acquire, develop and manufacture preclinical study and clinical trial materials, facilities, depreciation and other expenses including allocated expenses for rent and maintenance of facilities. Government grants are recognized as a reduction of the qualifying cost being reimbursed.

Patent Costs

Costs related to filing and pursuing patent applications are recorded as selling, general and administrative expense as incurred since the recoverability of such expenditures is uncertain.

Advertising and Product Promotion Costs

Advertising and product promotion costs are included in selling, general and administrative expenses and were $16,328 in the year ended December 31, 2016. Advertising and product promotion costs are expensed as incurred.

Stock‑Based Compensation

The Company accounts for grants of stock options, restricted stock awards and restricted stock units to employees, including members of the board of directors, based on their grant date fair value and recognizes compensation expense over their vesting period. The Company estimates the fair value of stock options as of the date of grant using the Black‑Scholes option pricing model and restricted stock awards and restricted stock units based on the fair value of the underlying common stock as determined by management or the value of the services provided, whichever is more readily determinable.

Stock‑based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight‑line basis, net of estimated forfeitures. The expense is adjusted for actual forfeitures as they occur.

For stock option grants with performance‑based milestones, the expense is recorded over the remaining service period after the point when the achievement of the milestone is probable or the performance condition has been achieved. For stock option grants with both performance‑based milestones and market conditions, expense is recorded over the derived service period after the point when the achievement of the performance‑based milestone is probable or the performance condition has been achieved.

The Company accounts for stock options and restricted stock awards to non‑employees using the fair value approach. Stock options and restricted stock awards to non‑employees are subject to periodic revaluation over their vesting terms. There were no non-employee grants in 2016 and there was one non-employee grant in 2015.

Income Taxes

The Company accounts for income taxes under the liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the years in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date.

The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax‑planning strategies and the absence of carryback available from results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future, in excess of its net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

The Company records uncertain tax positions on the basis of a two‑step process whereby (i) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (ii) for those tax positions that meet the more likely than not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company will recognize interest and penalties related to uncertain tax positions within income tax expense. Any accrued interest and penalties will be included within the related tax liability. As of December 31, 2016 and 2015, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in the Company’s statements of operations.

Net Loss per Common Share

Basic net loss per common share is calculated by dividing the net loss attributable to common shareholders by the weighted‑average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common shareholders by the weighted‑average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, stock options, warrants, redeemable convertible preferred stock and unvested restricted stock are considered potentially dilutive securities. Because the Company has reported a net loss for the years ended December 31, 2016, 2015 and 2014, diluted net loss per common share is the same as basic net loss per common share for those periods.

Diluted earnings per share is computed using the more dilutive of (i) the two‑class method, or (ii) the if‑converted method. The Company allocates earnings first to preferred shareholders based on dividend rights and then to common and preferred shareholders based on ownership interests. The weighted‑average number of common shares included in the computation of diluted earnings (loss) gives effect to all potentially dilutive common equivalent shares, including outstanding stock options, warrants, convertible redeemable preferred stock and the potential issuance of stock upon the conversion of the Company’s convertible notes. Common stock equivalent shares are excluded from the computation of diluted earnings (loss) per share if their effect is antidilutive.

Recently Issued Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2014-09 (ASC 606), Revenue from Contracts with Customers, which affects any entity that either enters into contracts with customers to transfer goods and services or enters into contracts for the transfer of nonfinancial assets. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers, which defers the effective date of ASU 2014-09 for all entities by one year. ASU 2014-09, which has been codified with the Accounting Standards Codification as Topic 606, is now effective for public companies for annual reporting periods beginning after December 15, 2017, including interim periods within those reporting periods. ASC 606 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. In addition, ASC 606 provides guidance on accounting for certain revenue-related costs including, but not limited to, when to capitalize costs associated with obtaining and fulfilling a contract. ASC 606 provides companies with two implementation methods. Companies can choose to apply the standard retrospectively to each prior reporting period presented (full retrospective application) or retrospectively with the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). Since ASU 2014-09 was issued, several additional ASUs have been issued and incorporated within ASC 606 to clarify various elements of the guidance. The Company anticipates that this standard will have a material impact on its consolidated financial statements with respect to inventory and deferred revenues and is continuing to assess all potential impacts of the standard, including evaluating the impact of each potential method of adoption on the Company’s consolidated financial statements and the impact to the pattern with which the Company will recognize revenue.

In August 2014, the FASB issued ASU No. 2014‑15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014‑15 requires management to evaluate, at each annual or interim reporting period, whether there are conditions or events that exist that raise substantial doubt about an entity’s ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures. ASU 2014‑15 is effective for annual periods ending after December 15, 2016 and earlier application is permitted. The Company adopted this standard during the three months ended December 31, 2016. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements.

In July 2015, the FASB issued ASU 2015-11, Simplifying the Measurement of Inventory. ASU 2015-11 applies to all inventory, except for inventory measured using the last-in, first-out method or the retail inventory method. The guidance allows an entity to measure inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in ASU 2015-11 are effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years, and may be applied prospectively with earlier adoption permitted. The Company adopted ASU 2015-11 during the three months ended June 30, 2016. The adoption of this ASU did not have a material impact on the Company’s consolidated balance sheets or statements of operations for the year ended and as of December 31, 2016.

In March 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2016-09, Compensation – Stock Compensation (Topic 718 Improvements to Employee Share-Based Payment Accounting). ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. Under this guidance, a company recognizes all excess tax benefits and tax deficiencies as income tax expense or benefit in the income statement. ASU 2016-09 is effective for public companies for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods; however, early adoption is permitted. The Company has early adopted ASU 2016-09 for its year ended December 31, 2016. The adoption of ASU 2016-09 did not have a material impact on the Company’s effective tax rate. In addition, the Company no longer calculates an estimate of expected forfeitures and began recongizing forfeitures as they occur. The recognition of forfeitures, as well as the cumulative-effect decrease to retained earnings with the offset to increase additional paid-in capital recognized upon adoption did not have a material impact on the Company’s consolidated balance sheets, statement of operations or cash flows for the year ended and as of December 31, 2016.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). ASU 2016-02 most significantly impacts lessee accounting and disclosures. First, this guidance requires lessees to identify arrangements that should be accounted for as leases. Under ASU 2016-02, for lease arrangements exceeding a 12-month term, a right-of-use asset and lease obligation is recorded by the lessee for all leases, whether operating or financing, while the income statement will reflect lease expense for operating leases and amortization/interest expense for financing leases. The balance sheet amount recorded for existing leases at the date of adoption of ASU 2016-02 must be calculated using the applicable incremental borrowing rate at the date of adoption. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. In addition, ASU 2016-02 requires the use of the modified retrospective method, which will require adjustment to all comparative periods presented in the consolidated financial statements. This guidance is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted for all entities. The Company has not chosen early adoption for this ASU and is currently evaluating its effect on the Company’s consolidated financial statements.

NET LOSS PER COMMON SHARE

12 Months Ended

Dec. 31, 2016

NET LOSS PER COMMON SHARE.

NET LOSS PER COMMON SHARE

3. NET LOSS PER COMMON SHARE

For the twelve months ended December 31, 2016, 2015 and 2014, these securities were anti‑dilutive due to the net losses in those periods and, therefore, the number of shares used to compute basic and diluted earnings per share are the same for of those periods.

The following table presents the computations of basic and dilutive net loss per share:



	Years ended December 31,
		2016		2015	2014
Net loss	$	(94,176)	$	(27,255)	$	(17,917)
Extinguishment of preferred stock - see Note 12		—		31,806		—
Accretion and dividends of prior preferred stock - See Note 12		—		(23,327)		(3,300)
Accretion and dividends of Series D preferred stock		—		(1,245)		—
Loss attributable to common shareholders — basic and diluted	$	(94,176)	$	(20,021)	$	(21,217)
Weighted-average number of common shares used in net loss per share - basic and diluted		24,262,945		13,542,282		933,997
Loss per share - basic and diluted	$	(3.88)	$	(1.48)	$	(22.72)

The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted‑average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares):



	Years ended December 31,
	2016	2015	2014
Outstanding stock options	2,326,801	1,452,149	281,029
Warrants	2,445	2,445	18,809
Redeemable convertible preferred stock	—	—	6,552,820
Unvested restricted stock	82,512	75,718	15,387
Restricted stock units	41,741	—	—

INVENTORY

12 Months Ended

Dec. 31, 2016

INVENTORY.

INVENTORY

4. INVENTORY

Inventory consisted of the following:


	As of December 31, 2016
Raw materials	$	294
Work in process		67
Finished goods		955
Total inventory	$	1,316

During the year ended December 31, 2016, the Company incurred aggregate charges of $100 related to excess inventory. These expenses were recorded as a component of cost of product revenues.

PREPAID EXPENSES AND OTHER CURRENT ASSETS

12 Months Ended

Dec. 31, 2016

PREPAID EXPENSES AND OTHER CURRENT ASSETS.

PREPAID EXPENSES AND OTHER CURRENT ASSETS

5. PREPAID EXPENSES AND OTHER CURRENT ASSETS

Prepaid expenses and other current assets consisted of the following:


	As of December 31,
	2016		2015
Prepaid regulatory fees	$	512	$	—
Prepaid development costs		485		—
Prepaid insurance		328		420
Other current assets		304		205
Other prepaid expenses		276		208
Deferred financing costs		—		353
Prepaid expenses and other current assets	$	1,905	$	1,186

PROPERTY AND EQUIPMENT

12 Months Ended

Dec. 31, 2016

PROPERTY AND EQUIPMENT.

PROPERTY AND EQUIPMENT

6. PROPERTY AND EQUIPMENT

Property and equipment consisted of the following:


	As of December 31,
	2016		2015
Machinery and equipment	$	863	$	755
Leasehold improvements		700		678
Computers and office equipment		590		262
Furniture and fixtures		117		117
Construction-in-process		100		—
Total property and equipment		2,370		1,812
Less: accumulated deprecation		(1,332)		(1,074)
Property and equipment, net	$	1,038	$	738

Depreciation expense related to property and equipment amounted to $258, $171 and $187 for the years ended December 31, 2016, 2015 and 2014, respectively.

INTANGIBLE ASSETS	12 Months Ended
INTANGIBLE ASSETS	Dec. 31, 2016
INTANGIBLE ASSETS.
INTANGIBLE ASSETS	7. INTANGIBLE ASSETS In May 2016, the Company entered into an agreement with BioDelivery Sciences International, Inc. (“BDSI”) to license the rights to develop, manufacture, and commercialize Onsolis® (fentanyl buccal soluble film), or Onsolis, in the United States. Onsolis is a Transmucosal Immediate-Release Fentanyl (“TIRF”) film indicated for the management of breakthrough pain in certain cancer patients. The Company expects to launch the product after the completion of the transfer of manufacturing and required submission to the FDA of a Prior Approval Supplement. Subject to FDA approval of the Prior Approval Supplement, the Company expects to launch Onsolis during the second half of 2017. In addition, during the term of the License Agreement, milestone payments in the aggregate amount of $21,000 may become payable by the Company subject to the satisfaction of certain commercialization, intellectual property, and net sales milestones, including $4,000 upon the first commercial sale of the product in the U.S. Finally, the Company will be required to pay royalties in the upper teens based on annual net sales of the product in the U.S. As of December 31, 2016, the Company has not satisfied the criteria of any milestones or royalties payable under the License Agreement and has not recognized any liabilities for such milestones or royalties payable in its consolidated financial statements. The Company made an upfront payment of $2,500 and is contractually committed to reimburse BDSI up to a maximum of $2,000 for its out-of-pocket expenses incurred in connection with the manufacturing transfer. The Company recorded the upfront payment as an intangible asset on the Consolidated Balance Sheet and will amortize it on a straight-line basis over the remaining patent life, a period of approximately 3.7 years. During the year ended December 31, 2016, the Company recognized amortization of expense of $397 related to the Onsolis intangible asset, which also represents the accumulated amortization to date. As of December 31, 2016, the remaining amortization period is approximately 3.1 years and estimated remaining amortization for 2017, 2018, 2019 and 2020 is expected to be $682, $682, $682, $57.

ACCRUED EXPENSES

12 Months Ended

Dec. 31, 2016

ACCRUED EXPENSES.

Accrued Expenses

8. ACCRUED EXPENSES

Accrued expenses consisted of the following:


	As of December 31,
	2016		2015
Accrued bonuses	$	2,210	$	1,474
Accrued incentive compensation		1,160		—
Accrued development costs		2,485		80
Accrued payroll and related benefits		1,217		93
Accrued sales and marketing		801		157
Accrued other operating costs		572		186
Accrued audit and legal		416		209
Accrued interest		18		29
Total accrued expenses	$	8,879	$	2,228

COMMITMENTS AND CONTINGENCIES

12 Months Ended

Dec. 31, 2016

COMMITMENTS AND CONTINGENCIES.

COMMITMENTS AND CONTINGENCIES

9. COMMITMENTS AND CONTINGENCIES

Legal Proceedings

From time to time, the Company may face legal claims or actions in the normal course of business. Except as disclosed below, the Company is not currently a party to any litigation and, accordingly, does not have any amounts recorded for any litigation related matters.

The Company’s NDA filing for Xtampza is a 505(b)(2) application, which allows the Company to reference data from an approved drug listed in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations (commonly known as the ‘‘Orange Book’’), in this case OxyContin OP. In connection with the 505(b)(2) process, the Company certified to the FDA and notified Purdue Pharma, L.P. (‘‘Purdue’’), as the holder of the NDA and any other Orange Book-listed patent owners, that the Company does not infringe any of the patents listed for OxyContin OP in the Orange Book. Under the Hatch-Waxman Act of 1984 (the ‘‘Hatch-Waxman Act’’), Purdue had the option to sue the Company for infringement and receive a stay of up to 30 months before the FDA could issue a final regulatory approval for Xtampza, unless the stay was earlier terminated. Purdue exercised its option and elected to sue the Company for infringement in the District of Delaware in March 2015 asserting infringement of three of Purdue’s Orange Book‑listed patents and one non-Orange Book-listed patent. In October 2015, the Delaware case was transferred to Massachusetts. After the Company filed a partial motion for judgment on the pleadings relating to the Orange Book-listed patents, the District Court of Massachusetts ordered judgment in favor of the Company on those three patents, and dismissed the claims asserting infringement of those patents with prejudice. Upon dismissal of those claims, the 30-month stay of FDA approval was lifted. As a result, the Company obtained final approval of its Xtampza ER products and has launched the products commercially.

In November 2015, Purdue filed a follow-on suit asserting infringement of another patent, Patent No. 9,073,933, which was late-listed in the Orange Book and therefore could not trigger any stay of FDA approval. In June 2016, Purdue filed another follow-on suit asserting infringement of another non-Orange Book listed patent, Patent No. 9,155,717. These suits were consolidated by the District of Massachusetts into the original action where Purdue’s infringement claim relating to the ’497 patent remains pending. Purdue continues to assert infringement of these three patents against the Company, none of which is associated with any stay of FDA approval. Purdue has made a demand for monetary relief but has not quantified their alleged damages. Purdue has also requested a judgment of infringement and an injunction on the sale of the Company’s products accused of infringement. The Company has denied all claims and seeks a judgment that the patents are invalid and/or not infringed by the Company, and seeks a judgment that the case is exceptional, with an award to the Company of its fees for defending the case.

The parties are in the early stages of fact discovery. Written discovery has commenced with depositions expected to commence in the first half of 2017. The parties are also in the claims construction stage of the patent litigation. The parties have briefed their proposed constructions and will argue their positions in front of the Court in the second quarter of 2017. The Company has also filed a motion for summary judgment that the asserted claims of the ’933, ’497, and ’717 patents are invalid and not infringed. The Company is not able to predict with certainty when the Court will decide the Company’s motion. No trial date has been scheduled.

The Company is, and plans to continue, defending this case vigorously. At this stage, we are unable to evaluate the likelihood of an unfavorable outcome or estimate the amount or range of potential loss, if any. At this time the Company is unable to provide meaningful quantification of how this potential litigation may impact its future financial condition, results of operations, or cash flows.

Operating Leases

The Company leases its office and research facility under a non‑cancellable operating lease. Terms of the agreement provide for an initial two‑month rent‑free period and future rent escalation, and provide that in addition to minimum lease rental payments, the Company is responsible for a pro‑rata share of operating expenses and taxes. In March 2015, the Company amended its lease to include an additional 9,660 square feet of space for a total of 19,335 square feet. In addition, the lease term was extended and now terminates on August 30, 2020. At the Company’s election, the lease term may be extended for an additional 5 -year term.

Aggregate minimum annual lease commitments of the Company under its non‑cancellable operating lease as of December 31, 2016 are as follows:



2017	$	226
2018		234
2019		241
2020		164
Total minimum lease payments	$	865

Rent expense under the operating lease agreement amounted to approximately $182, $112 and $69 for the years ended December 31, 2016, 2015 and 2014, respectively. In addition, the Company maintained a stand‑by letter of credit in connection with the Canton facility lease of $97 at December 31, 2016 and December 31, 2015. This amount is classified as restricted cash in the balance sheets.

Amounts provided by the lessor related to tenant improvements are considered inducements to enter into the lease. The Company has recorded these costs in the balance sheet as leasehold improvements, with the corresponding liabilities as deferred lease incentive and lease note payable. These liabilities are amortized on a straight‑line basis over the term of the lease.

TERM LOAN PAYABLE

12 Months Ended

Dec. 31, 2016

TERM LOAN PAYABLE.

TERM LOAN PAYABLE

10. TERM LOAN PAYABLE

On August 28, 2012, the Company entered into a loan agreement (“Original Term Loan”) with Silicon Valley Bank (“SVB”) to borrow up to a maximum amount of $1,000. In August 2012, October 2012 and February 2013, the Company borrowed $250, $250 and $500, respectively. The Original Term Loan bore interest at a rate per annum of 2.25% above the prime rate fixed at the time of advance of the Original Term Loan (5.50%). The Original Term Loan provided for interest‑only payments for the first 12 months based on the date of each borrowing, and, thereafter, 36 monthly payments of principal and interest. In connection with the Original Term Loan, the Company granted SVB a warrant to purchase 11,850 shares of common stock at an exercise price of $0.07 per share (See Note 11).

In January 2014, the Original Term Loan was amended (“Amendment No. 1”) to provide for the following: borrowings of up to $6,000, repayment in full of the Original Term Loan balance outstanding, and an adjustment of the variable interest rate from 2.25% above the prime rate to 1.75% above the prime rate. In February 2014, the Company borrowed $2,000. The proceeds from the initial borrowing were used to pay down the Original Term Loan balance outstanding resulting in the Company receiving $1,056. Borrowings under Amendment No. 1 bore interest at a rate of 5.0%. Amendment No. 1 provided for interest‑only payments for the first 12 months based on the date of each borrowing, and thereafter, 36 monthly payments of principal and interest. In connection with Amendment No. 1, the Company granted to SVB a warrant to purchase 14,430 shares of common stock with an exercise price of $0.05 per share (See Note 11).

In August 2014 the Original Term Loan was further amended (“Amendment No. 2”) to provide for total borrowings of up to $8,000. In August 2014 and September 2014 the Company drew down $3,000 and $3,000, respectively. Pursuant to Amendment No. 2, interest‑only payments are to be made for the first 12 months based on the date of each borrowing; thereafter, 36 monthly payments of principal and interest are to be made. Borrowings under Amendment 2 bear interest at the rate of 5.0%. The warrant agreement contains a performance clause that the Company met, resulting in additional financing extended and issuance of a warrant to purchase 86,580 additional shares of common stock with an exercise price of $0.05 per share (See Note 11).

In September 2014, the Original Term Loan was further amended (“Amendment No. 3”) to extend the loan draw period.

In November and December of 2014 the Company entered into a Note Purchase Agreement (the “Bridge Notes”) allowing for the issuance of $5,000 of convertible promissory notes to a group of investors (the “Holders”) bearing interest at a rate per annum of 6.0%. The Holders are related parties of the Company. In March 2015, in connection with the Series D convertible preferred stock financing, the Bridge Notes converted into 4,166,667 shares of Series D convertible preferred stock. Upon the conversion, the Company recognized a gain on extinguishment of $91. The accrued interest on the Bridge Notes was waived.

As of December 31, 2016, future payments under the Company’s term loan are as follows:


2017	$	2,667
2018		1,479
Balance	$	4,146

WARRANTS	12 Months Ended
WARRANTS	Dec. 31, 2016
WARRANTS.
WARRANTS	11. WARRANTS In November 2010, the Company issued a warrant to Comerica Bank. The warrant represents the right to purchase 2,445 shares of common stock with an exercise price of $12.27. The warrant expires in October 2017. In connection with the Term Loan Financings with Silicon Valley Bank, the Company issued warrants to purchase a total of 16,357 shares of common stock. In June 2015, SVB exercised all of its warrants.

EQUITY

12 Months Ended

Dec. 31, 2016

EQUITY.

EQUITY

12. EQUITY

Common Stock

As of December 31, 2016 and 2015, the Company had reserved the following shares of common stock for the issuance of common stock for the exercise of stock options and warrants and the issuance of shares under the 2015 Employee Stock Purchase Plan (in thousands):


	As of December 31,
	2016	2015
Options to purchase common stock	3,348	2,642
Employee stock purchase plan	364	200
Warrants	2	2
Total	3,714	2,844

Convertible Redeemable Preferred Stock

Series A, B and Series C Redeemable Convertible Preferred Stock

As of December 31, 2014, 54,481,000 shares of preferred stock were authorized, designated as Series A, Series B and Series C Preferred Stock of which 9,232,334, 27,324,237 and 8,658,008 were issued and outstanding, respectively.

In March 2015, the Company sold 41,666,667 shares of Series D convertible preferred stock for aggregate consideration of $50,000, comprised of $45,000 in cash and conversion of $5,000 in convertible notes with related parties. The convertible notes converted into 4,166,667 shares of Series D convertible preferred stock. The accrued interest on the convertible notes was waived. In this financing, the mandatory conversion for all series of preferred stock was modified so as to occur upon an initial public offering with gross proceeds in excess of $50,000.

STOCK BASED COMPENSATION

12 Months Ended

Dec. 31, 2016

STOCK BASED COMPENSATION.

STOCK BASED COMPENSATION

13. STOCK‑BASED COMPENSATION

Stock Options, Restricted Stock Awards and Restricted Stock Units

In May 2015, the Company adopted the Amended and Restated 2014 Stock Incentive Plan (the “Plan”), under which an aggregate of 2,700,000 shares of common stock were authorized for issuance to employees, officers, directors, consultants and advisors of the Company, plus an annual increase to be added on the first day of each fiscal year until the expiration of the Plan equal to 4% of the total number of outstanding shares of common stock on December 31st of the immediately preceding calendar year (or a lower amount as otherwise determined by the board of directors prior to January 1st). As of December 31, 2016, 1,021,509 shares of common stock were available for issuance pursuant to the Plan. The Plan provides for granting of both Internal Revenue Service qualified incentive stock options (“ISOs”) and non‑qualified options (“NQs”), restricted stock awards (“RSAs”) and restricted stock units (“RSUs”). Stock options generally vest over a four year period of service; however, certain options contain performance conditions. The options generally have a ten year contractual life and, upon termination, vested options are generally exercisable between one and three months following the termination date, while unvested options are forfeited immediately.

Stock option activity under the Plan is summarized as follows:


				Weighted-
			Weighted-	Average
			Average	Remaining		Aggregate
			Exercise Price	Contractual		Intrinsic
	Shares		per Share	Term (in years)		Value
Outstanding at December 31, 2015	1,452,149	$	10.37	10.4	$	24,887
Granted	1,063,981		16.46
Exercised	(81,831)		5.41
Cancelled	(107,498)		16.05
Outstanding at December 31, 2016	2,326,801	$	13.07	8.7	$	7,927
Exercisable at December 31, 2016	556,040	$	9.19	8.0	$	3,917
Vested and expected to vest at December 31, 2016	2,291,971	$	13.11	8.7	$	8,090

The total intrinsic value of stock options exercised for the year ended December 31, 2016 was $952. As of December 31, 2016, the unrecognized compensation cost related to outstanding options was $14,499, and is expected to be recognized as expense over approximately 2.8 years.

As of December 31, 2016, the weighted average fair value of vested options was $6.35. The weighted-average grant date fair value of options granted during the year ended December 31, 2016 was $10.98. The fair value of options that vested during the year ended December 31, 2016 was $7.37.

Restricted stock awards under the Plan are summarized as follows:


		Weighted-Average
		Purchase Price
	Shares	per Share
Unvested at December 31, 2015	75,718	$	5.73
Granted	—		—
Vested	(32,453)		5.73
Unvested at December 31, 2016 (1)	43,265	$	5.73

(1) Excludes 39,247 shares of unvested restricted stock remaining from the early exercise of stock options as of December 31, 2016.

The total fair value of restricted stock awards vested during the years ended December 31, 2016, was $186. As of December 31, 2016, the unrecognized compensation cost related to restricted stock awards was $233, and is expected to be recognized as expense over approximately 1.2 years.

Restricted stock units under the Plan are summarized as follows:


		Weighted-Average
	Shares	Grant Date Fair Value
Outstanding at December 31, 2015	—	$	—
Granted	41,741		16.15
Settled	—		—
Forfeited	—		—
Outstanding at December 31, 2016	41,741	$	16.15

As of December 31, 2016, the unrecognized compensation cost related to restricted stock units was $509, and is expected to be recognized as expense over approximately 3.0 years.

Employee Stock Purchase Plan

The Company’s 2015 Employee Stock Purchase Plan allows employees as designated by the Company’s Board of Directors to purchase shares of the Company’s common stock. The purchase price is equal to 85% of the lower of the closing price of our common stock on (1) the first day of the purchase period or (2) the last day of the purchase period. The first purchase period commenced in the year ended December 31, 2016. The expense for the year ended December 31, 2016 was $457.

Stock‑Based Compensation Expense

The Company granted stock options to employees for the years ended December 31, 2016, 2015 and 2014. The Company estimates the fair value of stock options as of the date of grant using the Black‑Scholes option pricing model and restricted stock awards and restricted stock units based on the fair value of the award. Stock options and restricted stock issued to non‑board member, non‑employees are accounted for using the fair value approach and are subject to periodic revaluation over their vesting terms.

Stock‑based compensation for all stock options, restricted stock awards, restricted stock units and for the employee stock purchase plan are reported within:


	Years ended December 31,
		2016		2015		2014
Research and development	$	638	$	223	$	12
Selling, general and administrative		5,149		1,986		10
Total stock-based compensation expense	$	5,787	$	2,209	$	22

The weighted‑average assumptions used in the Black‑Scholes option pricing model to determine the fair value of the employee stock option grants were as follows:


	Years ended December 31,
	2016		2015		2014
Risk-free interest rate	1.5	%	1.7	%	1.8	%
Volatility	76.3	%	77.0	%	77.1	%
Expected term (years)	6.02		6.20		6.25
Expected dividend yield	—	%	—	%	—	%

Risk‑free Interest Rate. The risk‑free interest rate assumption is based on observed interest rates appropriate for the expected term of the stock option grants.

Expected Volatility. Due to the Company’s limited operating history and lack of company‑specific historical or implied volatility, the expected volatility assumption is based on historical volatilities of a peer group of similar companies whose share prices are publicly available. The peer group was developed based on companies in the biotechnology and pharmaceutical industries. In evaluating similarity, we consider factors such as industry, stage of life cycle and size.

Expected Term. The expected term represents the period of time that options are expected to be outstanding. Because the Company does not have historical exercise behavior, through December 31, 2016 it determined the expected life assumption using the simplified method, which is an average of the contractual term of the option and its vesting period.

Expected Dividend Yield. The expected dividend yield assumption is based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

INCOME TAXES

12 Months Ended

Dec. 31, 2016

INCOME TAXES.

INCOME TAXES

14. INCOME TAXES

For the years ended December 31, 2016 and 2015, the Company did not record a current or deferred income tax expense or (benefit) due to current and historical losses incurred by the Company. The Company's losses before income taxes consist solely of domestic losses.

The Company has early adopted the provisions of ASU 2016-09, Compensation – Stock Compensation (Topic 718 Improvements to Employee Share-Based Payment Accounting), for its year ended December 31, 2016. ASU 2016-09 requires companies to include the benefit of an option deduction in its net operating loss carryforward deferred tax asset. Prior to its adoption of ASU 2016-09, the Company’s excess tax benefits associated with option deductions were maintained in the Company’s APIC pool of windfall tax benefits, which was tracked off balance sheet and not included in its deferred tax assets. As a result of the Company’s adoption of ASU 2016-09, it will track option deductions in its net operating loss deferred tax asset on a modified retrospective basis, and has included the option deductions in the December 31, 2016 deferred tax assets. The gross deferred tax asset and valuation allowance as of December 31, 2016 increased $406 as a result of the cumulative effect of adoption of ASU 2016-09. The Company has not recast its December 31, 2015 and December 31, 2014 deferred tax assets or its rate reconciliation, and therefore the option deductions in 2015 and 2014 are not included in the net operating loss deferred tax asset as originally reported. Since the Company has historically maintained a full valuation allowance on its net worldwide deferred tax asset, there is no net impact to retained earnings from the adoption of ASU 2016-09.

A reconciliation of income tax expense (benefit) computed at the statutory federal income tax rate to income taxes as reflected in the consolidated financial statements is as follows:


	As of December 31,
	2016		2015		2014
Federal income tax expense at statutory rate	34.00	%	34.00	%	34.00	%
(Increase) decrease income tax (benefit) resulting from:
State income tax, net of federal benefit	3.43		5.29		—
Permanent differences	(1.45)		(1.70)		(0.17)
Research and development credit	0.27		0.89		3.74
Change in valuation allowance	(36.25)		(38.48)		(37.57)
Effective income tax rate	0.00	%	0.00	%	0.00	%

Deferred taxes are recognized for temporary differences between the basis of assets and liabilities for financial statement and income tax purposes. The significant components of the Company’s deferred tax assets and liabilities are comprised of the following:


	As of December 31,
	2016		2015
Deferred tax assets:
U.S. and state net operating loss carryforwards	$	71,049	$	38,405
Research and development credits		3,712		3,421
Accruals and other		1,541		144
Depreciation and amortization		261		94
Total deferred tax assets		76,563		42,064
Valuation allowance		(76,563)		(42,064)
Net deferred tax assets	$	—	$	—

The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets. As of December 31, 2016 and 2015, based on the Company's history of operating losses, the Company has concluded that it is not more likely than not that the benefit of its deferred tax assets will be realized. Accordingly, the Company has provided a full valuation allowance for deferred tax assets as of December 31, 2016 and 2015. The valuation allowance increased $34,499 and $10,539, during the years ended December 31, 2016 and 2015 respectively, due primarily to net operating losses generated.

As of December 31, 2016, 2015 and 2014, the Company had U.S. federal net operating loss carryforwards of $190,926, $104,888 and $78,276, respectively, which may be available to offset future income tax liabilities and expire at various dates through 2036. As of December 31, 2016, 2015, and 2014, the Company also had U.S. state net operating loss carryforwards of $145,902, $59,875, and $34,184 respectively, which may be available to offset future income tax liabilities and expire at various dates through 2036. Included in the federal and state net operating loss carryforwards are approximately $1,539, $1,064, and $0, respectively, of deductions related to the exercise of stock options. As stated above, the company is electing to early adopt ASU 2016-09 on a modified retrospective basis. Therefore, the $1,539 of option deductions is included in the company’s net operating loss deferred tax asset at December 31, 2016. The company is not recasting its net operating loss deferred tax asset at December 31, 2015 and December 31, 2014, and therefore the option deduction of $1,064 and $0, respectively, is not included in the Company’s deferred tax assets.

As of December 31, 2016, 2015 and 2014, the Company had federal research and development tax credit carryforwards of approximately $3,367, $3,110, and $2,868, respectively, available to reduce future tax liabilities which expire at various dates through 2036. As of December 31, 2016, 2015 and 2014 the Company had state research and development tax credit carryforwards of approximately $522, $469 and $226, respectively, available to reduce future tax liabilities which expire at various dates through 2031.

Under the provisions of the Internal Revenue Code, the net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50 percent, as defined under Sections 382 and 383 of the Internal Revenue Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company has completed numerous financings since its inception which may have resulted in a change in control as defined by Sections 382 and 383 of the Internal Revenue Code, or could result in a change in control in the future.

For all years through December 31, 2016, the Company generated research credits but has not conducted a study to document the qualified activities. This study may result in an adjustment to the Company’s research and development credit carryforwards; however, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position for these two years. A full valuation allowance has been provided against the Company’s research and development credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the deferred tax asset established for the research and development credit carryforwards and the valuation allowance.

The Company files income tax returns in the United States and in several states. The federal and state income tax returns are generally subject to tax examinations for the tax years ended December 31, 2013 through December 31, 2016. To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the Internal Revenue Service or state tax authorities to the extent utilized in a future period.

EMPLOYEE BENEFITS	12 Months Ended
EMPLOYEE BENEFITS	Dec. 31, 2016
EMPLOYEE BENEFITS.
EMPLOYEE BENEFITS	15. EMPLOYEE BENEFITS The Company has a retirement savings plan, which is qualified under section 401(k) of the Code, for its employees. The plan allows eligible employees to defer, at the employee’s discretion, pretax compensation up to the Internal Revenue Service annual limits. Employees become eligible to participate after completing 3 months of service. The Company is not required to contribute to this plan. Total expense for contributions made by the Company the years ended December 31, 2016, 2015 and 2014 was $613, $44 and $35 respectively.

UNAUDITED QUARTERLY OPERATING RESULTS

12 Months Ended

Dec. 31, 2016

UNAUDITED QUARTERLY OPERATING RESULTS.

UNAUDITED QUARTERLY OPERATING RESULTS

16. UNAUDITED QUARTERLY OPERATING RESULTS

The following is a summary of unaudited quarterly results of operations for the years ended December 31, 2016 and 2015:


		First		Second		Third		Fourth
Year ended December 31, 2016		Quarter		Quarter		Quarter		Quarter
Product revenues, net	$	-	$	-	$	408	$	1,303

Costs and expenses
Cost of product revenues		-		-		29		184
Research and development		4,062		4,301		3,254		3,331
Selling, general and administrative		11,525		20,173		23,567		25,367
Total costs and expenses		15,587		24,474		26,850		28,882

Loss from operations	$	(15,587)	$	(24,474)	$	(26,442)	$	(27,579)
Other (expense) income, net		(66)		(46)		(2)		20
Net loss	$	(15,653)	$	(24,520)	$	(26,444)	$	(27,559)

Weighted-average shares - basic and diluted		23,130,153		23,417,378		23,460,340		27,100,231
Loss per share - basic and diluted	$	(0.68)	$	(1.05)	$	(1.13)	$	(1.02)

		First		Second		Third		Fourth
Year ended December 31, 2015		Quarter		Quarter		Quarter		Quarter
Costs and expenses
Research and development	$	1,445	$	1,641	$	3,358	$	1,531
Selling, general and administrative		2,186		2,934		5,907		7,905
Total costs and expenses		3,631		4,575		9,265		9,436

Loss from operations	$	(3,631)	$	(4,575)	$	(9,265)	$	(9,436)
Other expense, net		(63)		(99)		(97)		(89)
Net loss	$	(3,694)	$	(4,674)	$	(9,362)	$	(9,525)

Shares used in computing net loss per share-basic		1,001,704		11,791,546		20,531,406		20,558,205
Shares used in computing net loss per share-diluted		7,554,524		11,791,546		20,531,406		20,558,205
Net income (loss) per share-basic	$	0.34	$	(0.45)	$	(0.46)	$	(0.46)
Net loss per share-diluted	$	(0.65)	$	(0.45)	$	(0.46)	$	(0.46)

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2016
SUBSEQUENT EVENTS.
SUBSEQUENT EVENTS	17. SUBSEQUENT EVENTS The Company has concluded that no subsequent events have occurred that require disclosure.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2016

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES.

Use of Estimates

Fair Value Measurements

Level 1: Quoted prices in (unadjusted) active markets for identical assets or liabilities

Level 2: Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly.

Level 3: Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability.

Transfers are calculated on values as of the transfer date. There were no transfers between Levels 1, 2 and 3 during the years ended December 31, 2016 and 2015.

The following tables present the Company’s financial instruments carried at fair value using the lowest level input applicable to each financial instrument at December 31, 2016 and 2015.


						Significant
				Quoted Prices		other		Significant
				in active		observable		unobservable
				markets		inputs		inputs
Description		Total		(Level 1)		(Level 2)		(Level 3)
December 31, 2016
Money market funds, included in cash equivalents	$	125,515	$	125,515	$	—	$	—

December 31, 2015
Money market funds, included in cash equivalents	$	94,912	$	94,912	$	—	$	—

Concentration of Credit Risk

Cash and Cash Equivalents

Inventory

Property and Equipment


Asset Category	Estimated Useful Life
Machinery and equipment		5	years
Computers and office equipment		3 - 5	years
Furniture and fixtures		7	years
Leasehold improvements		Lesser of remaining lease term and estimated useful life

Upon retirement or sale, the cost of assets disposed and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is recorded in the statements of operations.

Intangible Assets

Restricted Cash

Revenue Recognition

Research and Development Costs

Patent Costs

Costs related to filing and pursuing patent applications are recorded as selling, general and administrative expense as incurred since the recoverability of such expenditures is uncertain.

Advertising and Product Promotion Costs

Stock-Based Compensation

Stock‑Based Compensation

Income Taxes

Net Loss per Common Share

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2016

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES.

Schedule of financial instruments measured at fair value by level within fair value hierarchy


						Significant
				Quoted Prices		other		Significant
				in active		observable		unobservable
				markets		inputs		inputs
Description		Total		(Level 1)		(Level 2)		(Level 3)
December 31, 2016
Money market funds, included in cash equivalents	$	125,515	$	125,515	$	—	$	—

December 31, 2015
Money market funds, included in cash equivalents	$	94,912	$	94,912	$	—	$	—

Schedule of estimated useful lives of property and equipment


Asset Category	Estimated Useful Life
Machinery and equipment		5	years
Computers and office equipment		3 - 5	years
Furniture and fixtures		7	years
Leasehold improvements		Lesser of remaining lease term and estimated useful life

NET LOSS PER COMMON SHARE (Tables)

12 Months Ended

Dec. 31, 2016

NET LOSS PER COMMON SHARE.

Schedule of computations of basic and diluted net loss per share



	Years ended December 31,
		2016		2015	2014
Net loss	$	(94,176)	$	(27,255)	$	(17,917)
Extinguishment of preferred stock - see Note 12		—		31,806		—
Accretion and dividends of prior preferred stock - See Note 12		—		(23,327)		(3,300)
Accretion and dividends of Series D preferred stock		—		(1,245)		—
Loss attributable to common shareholders — basic and diluted	$	(94,176)	$	(20,021)	$	(21,217)
Weighted-average number of common shares used in net loss per share - basic and diluted		24,262,945		13,542,282		933,997
Loss per share - basic and diluted	$	(3.88)	$	(1.48)	$	(22.72)

Schedule of potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding



	Years ended December 31,
	2016	2015	2014
Outstanding stock options	2,326,801	1,452,149	281,029
Warrants	2,445	2,445	18,809
Redeemable convertible preferred stock	—	—	6,552,820
Unvested restricted stock	82,512	75,718	15,387
Restricted stock units	41,741	—	—

INVENTORY (Tables)

12 Months Ended

Dec. 31, 2016

INVENTORY.

Schedule of Inventory


	As of December 31, 2016
Raw materials	$	294
Work in process		67
Finished goods		955
Total inventory	$	1,316

PREPAID EXPENSES AND OTHER CURRENT ASSETS (Tables)

12 Months Ended

Dec. 31, 2016

PREPAID EXPENSES AND OTHER CURRENT ASSETS.

Schedule of components of prepaid expenses and other current assets


	As of December 31,
	2016		2015
Prepaid regulatory fees	$	512	$	—
Prepaid development costs		485		—
Prepaid insurance		328		420
Other current assets		304		205
Other prepaid expenses		276		208
Deferred financing costs		—		353
Prepaid expenses and other current assets	$	1,905	$	1,186

PROPERTY AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2016

PROPERTY AND EQUIPMENT.

Schedule of components of property and equipment


	As of December 31,
	2016		2015
Machinery and equipment	$	863	$	755
Leasehold improvements		700		678
Computers and office equipment		590		262
Furniture and fixtures		117		117
Construction-in-process		100		—
Total property and equipment		2,370		1,812
Less: accumulated deprecation		(1,332)		(1,074)
Property and equipment, net	$	1,038	$	738

ACCRUED EXPENSES (Tables)

12 Months Ended

Dec. 31, 2016

ACCRUED EXPENSES.

Schedule of components of accrued expenses


	As of December 31,
	2016		2015
Accrued bonuses	$	2,210	$	1,474
Accrued incentive compensation		1,160		—
Accrued development costs		2,485		80
Accrued payroll and related benefits		1,217		93
Accrued sales and marketing		801		157
Accrued other operating costs		572		186
Accrued audit and legal		416		209
Accrued interest		18		29
Total accrued expenses	$	8,879	$	2,228

COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2016

COMMITMENTS AND CONTINGENCIES.

Schedule of aggregate minimum annual lease commitments under non-cancellable operating lease



2017	$	226
2018		234
2019		241
2020		164
Total minimum lease payments	$	865

TERM LOAN PAYABLE (Tables)

12 Months Ended

Dec. 31, 2016

TERM LOAN PAYABLE.

Schedule of future payments under debt agreements


2017	$	2,667
2018		1,479
Balance	$	4,146

EQUITY (Tables)

12 Months Ended

Dec. 31, 2016

EQUITY.

Schedule of shares of common stock reserved for future issuance


	As of December 31,
	2016	2015
Options to purchase common stock	3,348	2,642
Employee stock purchase plan	364	200
Warrants	2	2
Total	3,714	2,844

STOCK BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2016

Summary of restricted stock awards


		Weighted-Average
		Purchase Price
	Shares	per Share
Unvested at December 31, 2015	75,718	$	5.73
Granted	—		—
Vested	(32,453)		5.73
Unvested at December 31, 2016 (1)	43,265	$	5.73

Summary of stock option activity


				Weighted-
			Weighted-	Average
			Average	Remaining		Aggregate
			Exercise Price	Contractual		Intrinsic
	Shares		per Share	Term (in years)		Value
Outstanding at December 31, 2015	1,452,149	$	10.37	10.4	$	24,887
Granted	1,063,981		16.46
Exercised	(81,831)		5.41
Cancelled	(107,498)		16.05
Outstanding at December 31, 2016	2,326,801	$	13.07	8.7	$	7,927
Exercisable at December 31, 2016	556,040	$	9.19	8.0	$	3,917
Vested and expected to vest at December 31, 2016	2,291,971	$	13.11	8.7	$	8,090

Schedule of weighted-average assumptions used in Black-Scholes option-pricing model


	Years ended December 31,
	2016		2015		2014
Risk-free interest rate	1.5	%	1.7	%	1.8	%
Volatility	76.3	%	77.0	%	77.1	%
Expected term (years)	6.02		6.20		6.25
Expected dividend yield	—	%	—	%	—	%

Schedule of stock-based compensation for all stock options and restricted stock awards


	Years ended December 31,
		2016		2015		2014
Research and development	$	638	$	223	$	12
Selling, general and administrative		5,149		1,986		10
Total stock-based compensation expense	$	5,787	$	2,209	$	22

Restricted Stock Units (RSUs)

Summary of restricted stock awards


		Weighted-Average
	Shares	Grant Date Fair Value
Outstanding at December 31, 2015	—	$	—
Granted	41,741		16.15
Settled	—		—
Forfeited	—		—
Outstanding at December 31, 2016	41,741	$	16.15

INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2016

INCOME TAXES.

Schedule of reconciliation of income tax expense (benefit) at statutory federal income tax rate to income taxes


	As of December 31,
	2016		2015		2014
Federal income tax expense at statutory rate	34.00	%	34.00	%	34.00	%
(Increase) decrease income tax (benefit) resulting from:
State income tax, net of federal benefit	3.43		5.29		—
Permanent differences	(1.45)		(1.70)		(0.17)
Research and development credit	0.27		0.89		3.74
Change in valuation allowance	(36.25)		(38.48)		(37.57)
Effective income tax rate	0.00	%	0.00	%	0.00	%

Schedule of significant components of deferred tax assets and liabilities


	As of December 31,
	2016		2015
Deferred tax assets:
U.S. and state net operating loss carryforwards	$	71,049	$	38,405
Research and development credits		3,712		3,421
Accruals and other		1,541		144
Depreciation and amortization		261		94
Total deferred tax assets		76,563		42,064
Valuation allowance		(76,563)		(42,064)
Net deferred tax assets	$	—	$	—

UNAUDITED QUARTERLY OPERATING RESULTS (Tables)

12 Months Ended

Dec. 31, 2016

UNAUDITED QUARTERLY OPERATING RESULTS.

Summary of unaudited quarterly results of operations


		First		Second		Third		Fourth
Year ended December 31, 2016		Quarter		Quarter		Quarter		Quarter
Product revenues, net	$	-	$	-	$	408	$	1,303

Costs and expenses
Cost of product revenues		-		-		29		184
Research and development		4,062		4,301		3,254		3,331
Selling, general and administrative		11,525		20,173		23,567		25,367
Total costs and expenses		15,587		24,474		26,850		28,882

Loss from operations	$	(15,587)	$	(24,474)	$	(26,442)	$	(27,579)
Other (expense) income, net		(66)		(46)		(2)		20
Net loss	$	(15,653)	$	(24,520)	$	(26,444)	$	(27,559)

Weighted-average shares - basic and diluted		23,130,153		23,417,378		23,460,340		27,100,231
Loss per share - basic and diluted	$	(0.68)	$	(1.05)	$	(1.13)	$	(1.02)

		First		Second		Third		Fourth
Year ended December 31, 2015		Quarter		Quarter		Quarter		Quarter
Costs and expenses
Research and development	$	1,445	$	1,641	$	3,358	$	1,531
Selling, general and administrative		2,186		2,934		5,907		7,905
Total costs and expenses		3,631		4,575		9,265		9,436

Loss from operations	$	(3,631)	$	(4,575)	$	(9,265)	$	(9,436)
Other expense, net		(63)		(99)		(97)		(89)
Net loss	$	(3,694)	$	(4,674)	$	(9,362)	$	(9,525)

Shares used in computing net loss per share-basic		1,001,704		11,791,546		20,531,406		20,558,205
Shares used in computing net loss per share-diluted		7,554,524		11,791,546		20,531,406		20,558,205
Net income (loss) per share-basic	$	0.34	$	(0.45)	$	(0.46)	$	(0.46)
Net loss per share-diluted	$	(0.65)	$	(0.45)	$	(0.46)	$	(0.46)

NATURE OF BUSINESS (Details) $ / shares in Units, $ in Thousands	1 Months Ended
	Oct. 31, 2016 USD ($) $ / shares shares	Jan. 31, 2016 USD ($) $ / shares shares	May 31, 2015 USD ($) $ / shares shares	Apr. 30, 2015	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Common stock split ratio				0.1449
Accumulated deficit
Accumulated deficit \| $					$ 223,184	$ 129,008
Initial public offering
Stock Issued During Period, Shares, New Issues	5,750,000	2,750,000	6,670,000
Issue price (in dollars per share) \| $ / shares	$ 16.00	$ 20.00	$ 12.00
Net proceeds from IPO \| $	$ 86,166	$ 51,174	$ 72,029
Conversion into common stock			12,591,463
Underwriters over-allotment option
Stock Issued During Period, Shares, New Issues			870,000

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended				12 Months Ended
	Oct. 31, 2016 $ / shares shares	Jan. 31, 2016 $ / shares shares	May 31, 2015 $ / shares shares	Apr. 30, 2015	Dec. 31, 2016 USD ($) customer	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Stockholders' Equity Note, Stock Split, Conversion Ratio				0.1449
Marketing and Advertising Expense					$ 16,328
Allocated Share-based Compensation Expense					5,787	$ 2,209	$ 22
Inventory Adjustments					100
Inventory capitalized					$ 1,316
Finite-Lived Intangible Asset, Useful Life					3 years 8 months 12 days
Fair value measurements
Financial instruments with off balance sheet risk of loss, assets					$ 0
Financial instruments with off balance sheet risk of loss, liabilities					$ 0
Accounts Receivable \| Customer Concentration Risk
Number of customers \| customer					3
Accounts Receivable \| Customer Concentration Risk \| Customer One [Member]
Risk Percentage					44.00%
Accounts Receivable \| Customer Concentration Risk \| Customer Two [Member]
Risk Percentage					27.00%
Accounts Receivable \| Customer Concentration Risk \| Customer Three [Member]
Risk Percentage					21.00%
Revenue \| Customer Concentration Risk
Number of customers \| customer					3
Revenue \| Customer Concentration Risk \| Customer One [Member]
Risk Percentage					35.00%
Revenue \| Customer Concentration Risk \| Customer Two [Member]
Risk Percentage					28.00%
Revenue \| Customer Concentration Risk \| Customer Three [Member]
Risk Percentage					27.00%
Initial public offering
Stock Issued During Period, Shares, New Issues \| shares	5,750,000	2,750,000	6,670,000
Shares Issued, Price Per Share \| $ / shares	$ 16.00	$ 20.00	$ 12.00
Underwriters over-allotment option
Stock Issued During Period, Shares, New Issues \| shares			870,000

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Financial Instruments Carried at Fair Value (Details) - Estimate of fair value - Money market funds - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair value measurements
Cash and cash equivalents	$ 125,515	$ 94,912
Quoted Prices in active markets (Level 1)
Fair value measurements
Cash and cash equivalents	$ 125,515	$ 94,912

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
Machinery and equipment
Property and Equipment
Estimated Useful Life	5 years
Computers and office equipment \| Minimum
Property and Equipment
Estimated Useful Life	3 years
Computers and office equipment \| Maximum
Property and Equipment
Estimated Useful Life	5 years
Furniture and fixtures
Property and Equipment
Estimated Useful Life	7 years

NET LOSS PER COMMON SHARE - Computation of Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net loss per common share
Net loss	$ (27,559)	$ (26,444)	$ (24,520)	$ (15,653)	$ (9,525)	$ (9,362)	$ (4,674)	$ (3,694)	$ (94,176)	$ (27,255)	$ (17,917)
Extinguishment of preferred stock										31,806
Accretion of prior preferred stock										(23,327)	(3,300)
Loss attributable to common shareholders — basic and diluted									$ (94,176)	$ (20,021)	$ (21,217)
Weighted-average number of common shares used in net loss per share-basic and diluted (in shares)	27,100,231	23,460,340	23,417,378	23,130,153					24,262,945	13,542,282	933,997
(Loss) earnings per share - basic					$ (0.46)	$ (0.46)	$ (0.45)	$ 0.34	$ (3.88)	$ (1.48)	$ (22.72)
Series D convertible redeemable preferred stock
Net loss per common share
Accretion of prior preferred stock										$ (1,245)

NET LOSS PER COMMON SHARE - Summary of Potentially Dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock options
Anti-dilutive securities
Potentially dilutive securities excluded from the computations of diluted weighted-average shares outstanding	2,326,801	1,452,149	281,029
Warrants
Anti-dilutive securities
Potentially dilutive securities excluded from the computations of diluted weighted-average shares outstanding	2,445	2,445	18,809
All series of convertible redeemable preferred stock
Anti-dilutive securities
Potentially dilutive securities excluded from the computations of diluted weighted-average shares outstanding			6,552,820
Restricted Stock Award
Anti-dilutive securities
Potentially dilutive securities excluded from the computations of diluted weighted-average shares outstanding	41,741

INVENTORY (Details) $ in Thousands	Dec. 31, 2016 USD ($)
INVENTORY.
Raw materials	$ 294
Work in process	67
Finished goods	955
Total inventory	$ 1,316

PREPAID EXPENSES AND OTHER CURRENT ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
PREPAID EXPENSES AND OTHER CURRENT ASSETS.
Prepaid PDUFA fees	$ 512
Prepaid development costs	485
Prepaid Insurance	328	$ 420
Other current assets	304	205
Other prepaid expenses	276	208
Deferred financing costs		353
Total prepaid expenses and other current assets	$ 1,905	$ 1,186

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property and Equipment
Total property and equipment	$ 2,370	$ 1,812
Less: accumulated deprecation	(1,332)	(1,074)
Property and equipment, net	1,038	738
Depreciation and amortization	258	171	$ 187
Machinery and equipment
Property and Equipment
Total property and equipment	863	755
Leasehold improvements
Property and Equipment
Total property and equipment	700	678
Computers and office equipment
Property and Equipment
Total property and equipment	590	262
Furniture and fixtures
Property and Equipment
Total property and equipment	117	$ 117
Construction-in-process
Property and Equipment
Total property and equipment	$ 100

INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	May 31, 2016	Dec. 31, 2016
INTANGIBLE ASSETS.
Milestone payments payable contingent on the satisfaction of certain commercialization, intellectual property, and net sales milestones	$ 21,000
Milestone payment contingent on the first commercial sale of the product in the U.S.	4,000
Upfront payment classified as an intangible asset	2,500
Maximum reimbursement amount for out-of-pocket expenses	$ 2,000
Remaining amortization period	3 years 8 months 12 days	3 years 1 month 6 days
Amortization expense		$ 397
Estimated amortization for 2017		682
Estimated amortization for 2018		682
Estimated amortization for 2019		682
Estimated amortization for 2020		$ 57

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ACCRUED EXPENSES.
Accrued bonuses	$ 2,210	$ 1,474
Accrued incentive compensation	1,160
Accrued development costs	2,485	80
Accrued payroll and related benefits	1,217	93
Accrued sales and marketing	801	157
Accrued other operating costs	572	186
Accrued audit and legal	416	209
Accrued interest	18	29
Total accrued expenses	$ 8,879	$ 2,228

COMMITMENTS AND CONTINGENCIES - Minimum Annual Lease Commitments (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2015 ft²	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Lease
Rent-free term		2 months
Aggregate minimum annual lease commitments under non cancellable operating lease
2017		$ 226
2018		234
2019		241
2020		164
Total minimum lease payments		865
Rent expense under operating lease agreement
Rent expense		182	$ 112	$ 69
Guarantees
Restricted cash		97	$ 97
Amendment to office and research facility operating lease
Lease
Square of feet of space \| ft²	9,660
Office and research facility operating lease
Lease
Square of feet of space \| ft²	19,335
Term of lease extension option	5 years
Stand-by letter of credit
Guarantees
Restricted cash		$ 97

TERM LOAN PAYABLE (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended								2 Months Ended	12 Months Ended
	Aug. 28, 2012	Mar. 31, 2015	Sep. 30, 2014	Aug. 31, 2014	Feb. 28, 2014	Jan. 31, 2014	Feb. 28, 2013	Oct. 31, 2012	Aug. 31, 2012	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Loan and Security Agreements
Maximum borrowing capacity	$ 1,000
Proceeds from notes payable, net of original note payoff												$ 7,056
Exercise price of warrant (in dollars per share)													$ 12.27
Gain on extinguishment											$ 91
Common stock warrant, Silicon Valley Bank, Original Term Loan
Loan and Security Agreements
Common stock that may be purchased upon exercise of warrant (in shares)	11,850
Exercise price of warrant (in dollars per share)	$ 0.07
Common stock warrant, Silicon Valley Bank, Term Loan, Amendment No. 1
Loan and Security Agreements
Common stock that may be purchased upon exercise of warrant (in shares)					14,430
Exercise price of warrant (in dollars per share)					$ 0.05
Common stock warrant, Silicon Valley Bank, Term Loan, Amendment No. 2
Loan and Security Agreements
Common stock that may be purchased upon exercise of warrant (in shares)				86,580
Exercise price of warrant (in dollars per share)				$ 0.05
Series D convertible redeemable preferred stock
Loan and Security Agreements
Public offering of common stock, net of issuance costs, shares		4,166,667
6.0% Convertible promissory notes
Loan and Security Agreements
Gain on extinguishment		$ 91
6.0% Convertible promissory notes \| Bridge Notes Purchase Agreement \| Investors
Loan and Security Agreements
Amount issued										$ 5,000
Stated interest rate										6.00%
Term loan \| Silicon Valley Bank loan agreement
Loan and Security Agreements
Maximum borrowing capacity	$ 1,000
Amount borrowed							$ 500	$ 250	$ 250
Initial period of interest only payments	12 months
Subsequent period of principal and interest payments	36 months
Term loan \| Silicon Valley Bank loan agreement \| Prime
Loan and Security Agreements
Variable interest rate margin (as a percent)											2.25%	2.25%
Interest rate (as a percent)	5.50%
Term loan \| Silicon Valley Bank loan agreement, Amendment No. 1
Loan and Security Agreements
Maximum borrowing capacity						$ 6,000
Amount borrowed					$ 2,000
Proceeds from notes payable, net of original note payoff					$ 1,056
Initial period of interest only payments					12 months
Subsequent period of principal and interest payments					36 months
Term loan \| Silicon Valley Bank loan agreement, Amendment No. 1 \| Prime
Loan and Security Agreements
Variable rate basis						1.75%
Interest rate (as a percent)					5.00%
Term loan \| Silicon Valley Bank loan agreement Amendment No. 2
Loan and Security Agreements
Maximum borrowing capacity				$ 8,000
Amount borrowed			$ 3,000	$ 3,000
Initial period of interest only payments				12 months
Subsequent period of principal and interest payments				36 months
Term loan \| Silicon Valley Bank loan agreement Amendment No. 2 \| Prime
Loan and Security Agreements
Interest rate (as a percent)				5.00%

TERM LOAN PAYABLE (Details) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	12 Months Ended
TERM LOAN PAYABLE (Details) - USD ($) $ in Thousands	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2015
Related party transactions
Gain on extinguishment			$ 91
6.0% Convertible promissory notes
Related party transactions
Gain on extinguishment	$ 91
Bridge Notes Purchase Agreement \| Investors \| 6.0% Convertible promissory notes
Related party transactions
Amount issued		$ 5,000
Stated interest rate		6.00%

TERM LOAN PAYABLE - Future Payments (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Future payments under term loan
2017	$ 2,667
2018	1,479
Total	$ 4,146

WARRANTS (Details) - $ / shares	Dec. 31, 2016	Aug. 28, 2012
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	2,445
Exercise price of warrant (in dollars per share)	$ 12.27
Common stock warrant, Silicon Valley Bank, Original Term Loan
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	16,357
Exercise price of warrant (in dollars per share)		$ 0.07

EQUITY (Details) $ / shares in Units, $ in Thousands	1 Months Ended					12 Months Ended
EQUITY (Details) $ / shares in Units, $ in Thousands	Oct. 31, 2016 USD ($) $ / shares shares	Jan. 31, 2016 USD ($) $ / shares shares	May 31, 2015 USD ($) $ / shares shares	Apr. 30, 2015	Mar. 31, 2015 USD ($) shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 shares
Equity
Authorized common stock (in shares)						100,000,000	100,000,000
Par value of common stock (in dollars per share) \| $ / shares						$ 0.001	$ 0.001
Common stock issued (in shares)						29,364,100	20,739,351
Net proceeds from public offering \| $						$ 137,340	$ 72,029
Common stock outstanding (in shares)						29,364,100	20,739,351
Authorized preferred stock (in shares)								54,481,000
Common stock split ratio				0.1449
Common stock reserved for future issuance (in shares)						3,714	2,844
Employee stock purchase plan
Equity
Common stock reserved for future issuance (in shares)						364	200
Initial public offering
Equity
Public offering of common stock, net of issuance costs, shares	5,750,000	2,750,000	6,670,000
Issue price (in dollars per share) \| $ / shares	$ 16.00	$ 20.00	$ 12.00
Net proceeds from IPO \| $	$ 86,166	$ 51,174	$ 72,029
Conversion into common stock			12,591,463
Underwriters over-allotment option
Equity
Public offering of common stock, net of issuance costs, shares			870,000
Employee stock options
Equity
Common stock reserved for future issuance (in shares)						3,348	2,642
Warrants
Equity
Common stock reserved for future issuance (in shares)						2	2
Series A convertible redeemable preferred stock
Equity
Preferred stock issued (in shares)								9,232,334
Preferred stock outstanding (in shares)								9,232,334
Series B convertible redeemable preferred stock
Equity
Preferred stock issued (in shares)								27,324,237
Preferred stock outstanding (in shares)								27,324,237
Series C convertible redeemable preferred stock
Equity
Preferred stock issued (in shares)								8,658,008
Preferred stock outstanding (in shares)								8,658,008
Series D convertible redeemable preferred stock
Equity
Aggregate consideration \| $					$ 50,000		$ 44,807
Proceeds from Issuance of Convertible Preferred Stock \| $					$ 45,000
Conversion into bridge notes					5,000,000
Public offering of common stock, net of issuance costs, shares					4,166,667

EQUITY - Redeemeble Preferred (Details) $ in Thousands	1 Months Ended		12 Months Ended
EQUITY - Redeemeble Preferred (Details) $ in Thousands	Apr. 30, 2015	Mar. 31, 2015 shares	Dec. 31, 2015 USD ($) shares
Performance Adjustment
Performance adjustment ratio	0.1449
Series D convertible redeemable preferred stock
Preferred stock
Issuance of stock (in shares) \| shares		41,666,667	37,500,000
Closing costs \| $			$ 193

STOCK BASED COMPENSATION - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Stock-based compensation
Employee Stock Purchase Plan, Purchase Price Percentage		85.00%
Employee Stock Purchase Plan, Compensation Expense		$ 457
Stock options
Stock-based compensation
Shares of common stock authorized for issuance outstanding (in shares)		2,326,801	1,452,149
Vesting period		4 years
Contractual life		10 years
Stock options \| Minimum
Stock-based compensation
Period following termination date vested options are exercisable		1 month
Stock options \| Maximum
Stock-based compensation
Period following termination date vested options are exercisable		3 months
2014 Stock Incentive Plan
Stock-based compensation
Shares of common stock authorized for issuance (in shares)	2,700,000	1,021,509
Increase in number of authorized shares on the first day of each fiscal year, as a percentage of outstanding common stock (as a percent)	4.00%

STOCK BASED COMPENSATION - Summary of Stock Option Activity (Details) - Stock options - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Stock option activity
Outstanding at beginning of year (in shares)	1,452,149
Granted (in shares)	1,063,981
Exercised (in shares)	(81,831)
Cancelled (in shares)	(107,498)
Outstanding at end of period (in shares)	2,326,801	1,452,149
Exercisable at end of period (in shares)	556,040
Vested and expected to vest at end of period (in shares)	2,291,971
Weighted average exercise price per share
Outstanding at beginning of year (in dollars per share)	$ 10.37
Granted (in dollars per share)	16.46
Exercised (in dollars per share)	5.41
Cancelled (in dollars per share)	16.05
Outstanding at end of period (in dollars per share)	13.07	$ 10.37
Exercisable at end of period (in dollars per share)	9.19
Vested and expected to vest at end of period (in dollars per share)	$ 13.11
Stock option activity, additional information
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 952
Outstanding Weighted-average remaining contractual term	8 years 8 months 12 days	10 years 4 months 24 days
Exercisable at end of period, Weighted-average remaining contractual term	8 years
Vested and expected to vest at end of period, Weighted-average remaining contractual term	8 years 8 months 12 days
Outstanding Aggregate Intrinsic Value	$ 7,927	$ 24,887
Exercisable at end of period, Aggregate Intrinsic Value	3,917
Vested and expected to vest at end of period, Aggregate Intrinsic Value	8,090
Unrecognized compensation cost related to outstanding options	$ 14,499
Period over which unrecognized compensation cost is expected to be recognized as expense	2 years 9 months 18 days
Weighted average fair value of vested options (in dollars per share)	$ 6.35
Weighted-average grant date fair value per share of employee option grants (in dollars per share)	$ 10.98

STOCK BASED COMPENSATION - Summary of Restricted Stock Units (RSUs) Activity (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Shares vested
Total fair value of shares vested \| $	$ 7.37
Restricted Stock Award
Restricted stock awards
Balance at beginning of year (in shares)	75,718
Settled (in shares)	(32,453)
Balance at end of year (in shares)	43,265
Unvested remaining from the early exercise of stock options (in shares)	39,247
Weighted-average purchase price per share
Balance at beginning of year (in dollars per share) \| $ / shares	$ 5.73
Settled (in dollars per share) \| $ / shares	5.73
Balance at end of year (in dollars per share) \| $ / shares	$ 5.73
Unrecognized compensation cost
Unrecognized stock-based compensation expense \| $	$ 233,000
Period over which unrecognized compensation cost is expected to be recognized as expense	1 year 2 months 12 days
Shares vested
Total fair value of shares vested \| $	$ 186,000
Restricted Stock Units (RSUs)
Restricted stock awards
Granted (in shares)	41,741
Balance at end of year (in shares)	41,741
Weighted-average purchase price per share
Granted (in dollars per share) \| $ / shares	$ 16.15
Balance at end of year (in dollars per share) \| $ / shares	$ 16.15
Unrecognized compensation cost
Unrecognized stock-based compensation expense \| $	$ 509,000
Period over which unrecognized compensation cost is expected to be recognized as expense	3 years

STOCK BASED COMPENSATION - Summary of Valuation Assumptions Used (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants
Risk-free interest rate	1.50%	1.70%	1.80%
Volatility	76.30%	77.00%	77.10%
Expected term (in years)	6 years 7 days	6 years 2 months 12 days	6 years 3 months
Total stock-based compensation expense	$ 5,787	$ 2,209	$ 22
Research and development
Weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants
Total stock-based compensation expense	638	223	12
General and administrative
Weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants
Total stock-based compensation expense	$ 5,149	$ 1,986	$ 10

INCOME TAXES (Reconciliation of Income Tax Expense (Benefit) Computed at Statutory Federal Rate) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of income tax expense (benefit) computed at the statutory federal income tax rate to income taxes as reflected in the financial statements
Federal income tax (benefit) at statutory rate (as a percent)	34.00%	34.00%	34.00%
State income tax, net of federal benefit	3.43%	5.29%
Permanent items (as a percent)	(1.45%)	(1.70%)	(0.17%)
Research and development credits	0.27%	0.89%	3.74%
Change in valuation allowance (as a percent)	(36.25%)	(38.48%)	(37.57%)
Income tax expense (benefit) (as a percent)	0.00%	0.00%	0.00%

INCOME TAXES (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carryforwards	$ 71,049	$ 38,405
Research and development credits	3,712	3,421
Accruals and other	1,541	144
Depreciation and amortization	261	94
Deferred tax assets before valuation allowance	76,563	42,064
Valuation allowance	(76,563)	(42,064)
Deferred tax liabilities:
Net deferred tax assets	0	0
Valuation allowance
Increase to gross deferred tax asset and valuation allowance resulting from adoption of ASU 2016-09	406
Deferred tax asset valuation allowance increase	(34,499)	(10,539)
Net operating loss carryforwards
Operating Loss Carryforwards	1,539	1,064	$ 0
U.S. federal
Deferred tax assets:
Research and development credits	3,367	3,110	2,868
Net operating loss carryforwards
Available net operating loss carryforwards as of the end of the year	190,926	104,888	78,276
State
Deferred tax assets:
Research and development credits	522	469	226
Net operating loss carryforwards
Available net operating loss carryforwards as of the end of the year	$ 145,902	$ 59,875	$ 34,184

EMPLOYEE BENEFITS (Details) - USD ($) $ in Thousands	12 Months Ended
EMPLOYEE BENEFITS (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
EMPLOYEE BENEFITS.
Requisite service period of employees to be eligible to participate in the 401(k) plan	3 months
Total expense for contributions made to 401(k) plan	$ 613	$ 44	$ 35

UNAUDITED QUARTERLY OPERATING RESULTS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
UNAUDITED QUARTERLY OPERATING RESULTS.
Product revenues, net	$ 1,303	$ 408							$ 1,711
Cost of product revenues	184	29							213
Research and development	3,331	3,254	$ 4,301	$ 4,062	$ 1,531	$ 3,358	$ 1,641	$ 1,445	14,948	$ 7,975	$ 14,959
Selling, general and administrative	25,367	23,567	20,173	11,525	7,905	5,907	2,934	2,186
Total costs and expenses	28,882	26,850	24,474	15,587	9,436	9,265	4,575	3,631	95,793	26,907	17,665
Loss from operations	(27,579)	(26,442)	(24,474)	(15,587)	(9,436)	(9,265)	(4,575)	(3,631)	(94,082)	(26,907)	(17,665)
Other expense, net	20	(2)	(46)	(66)	(89)	(97)	(99)	(63)	(94)	(348)	(252)
Net loss	$ (27,559)	$ (26,444)	$ (24,520)	$ (15,653)	$ (9,525)	$ (9,362)	$ (4,674)	$ (3,694)	$ (94,176)	$ (27,255)	$ (17,917)
Weighted-average number of common shares used in net loss per share - basic					20,558,205	20,531,406	11,791,546	1,001,704
Weighted Average Number of Shares Outstanding, Basic					20,558,205	20,531,406	11,791,546	1,001,704
Shares used in computing net loss per share-diluted (in shares)					20,558,205	20,531,406	11,791,546	7,554,524
Earnings (loss) per share - basic					$ (0.46)	$ (0.46)	$ (0.45)	$ 0.34	$ (3.88)	$ (1.48)	$ (22.72)
Earnings (loss) per share - diluted					$ (0.46)	$ (0.46)	$ (0.45)	$ (0.65)
Weighted-average shares - basic and diluted	27,100,231	23,460,340	23,417,378	23,130,153					24,262,945	13,542,282	933,997
Loss per share - basic and diluted	$ (1.02)	$ (1.13)	$ (1.05)	$ (0.68)					$ (3.88)	$ (1.48)	$ (22.72)