Trevena (TRVN) 10-Q 3 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 31, 2017
Document and Entity Information
Entity Registrant Name	TREVENA INC
Entity Central Index Key	1,429,560
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		59,696,065
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 14,037	$ 24,266
Marketable securities	70,163	86,335
Prepaid expenses and other current assets	3,462	1,788
Total current assets	87,662	112,389
Property and equipment, net	2,921	1,059
Restricted cash	1,413	1,193
Intangible asset, net	12	13
Total assets	92,008	114,654
Current liabilities:
Accounts payable	2,290	8,749
Accrued expenses and other current liabilities	2,822	8,208
Current portion of loans payable, net	7,093	5,039
Deferred rent	56	52
Total current liabilities	12,261	22,048
Loans payable, net	20,895	13,270
Capital leases, net of current portion	15	18
Deferred rent, net of current portion	2,465	187
Warrant liability	19	75
Other long term liabilities	747	475
Total liabilities	36,402	36,073
Commitments and contingencies (Note 6)
Stockholders’ equity:
Common stock—$0.001 par value; 100,000,000 shares authorized, 59,456,364 and 55,768,414 shares issued and outstanding at June 30, 2017 and December 31, 2016, respectively	59	56
Preferred stock—$0.001 par value; 5,000,000 shares authorized, none issued or outstanding at June 30, 2017 and December 31, 2016	0	0
Additional paid-in capital	382,375	364,148
Accumulated deficit	(326,771)	(285,625)
Accumulated other comprehensive income (loss)	(57)	2
Total stockholders’ equity	55,606	78,581
Total liabilities and stockholders’ equity	$ 92,008	$ 114,654

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	59,456,364	55,768,414
Common stock, shares outstanding (in shares)	59,456,364	55,768,414
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

Statements of Operations and Co

Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenue:
Collaboration revenue	$ 0	$ 1,875	$ 0	$ 3,750
Total revenue	0	1,875	0	3,750
Operating expenses:
General and administrative	4,385	3,697	9,264	7,615
Research and development	15,499	17,203	31,595	32,956
Total operating expenses	19,884	20,900	40,859	40,571
Loss from operations	(19,884)	(19,025)	(40,859)	(36,821)
Other income (expense):
Change in fair value of warrant liability	19	28	56	70
Net (loss) gain on asset disposals	1	0	1	0
Miscellaneous income	0	0	628	222
Interest income	163	214	337	407
Interest expense	(731)	(433)	(1,309)	(873)
Total other expense	(548)	(191)	(287)	(174)
Net loss attributable to common stockholders	(20,432)	(19,216)	(41,146)	(36,995)
Other comprehensive (loss) income, net:
Unrealized gain (loss) on marketable securities	(8)	45	(59)	281
Other comprehensive (loss) income	(8)	45	(59)	281
Comprehensive loss	$ (20,440)	$ (19,171)	$ (41,205)	$ (36,714)
Per share information:
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.35)	$ (0.37)	$ (0.71)	$ (0.71)
Weighted average common shares outstanding, basic and diluted (in shares)	58,381,868	52,174,569	57,642,379	51,762,467

Statement of Stockholders_ Equi

Statement of Stockholders’ Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Common stock, shares issued (in shares)	55,768,414	55,768,414
Balance, beginning of period (in shares) at Dec. 31, 2016	55,768,414
Balance, beginning of period at Dec. 31, 2016	$ 78,581	$ 56	$ 364,148	$ (285,625)	$ 2
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	$ 3,687		3,687
Exercise of stock options (in shares)	283,995	283,995
Exercise of stock options	$ 355		355
Net issuance of common stock warrant	501		501
Issuance of common stock, net of issuance costs (in shares)		3,403,955
Issuance of common stock, net of issuance costs	13,687	$ 3	13,684
Unrealized gain (loss) on marketable securities	(59)				(59)
Net loss	$ (41,146)			(41,146)
Balance, end of period (in shares) at Jun. 30, 2017	59,456,364	59,456,364
Balance, end of period at Jun. 30, 2017	$ 55,606	$ 59	$ 382,375	$ (326,771)	$ (57)
Common stock, shares issued (in shares)	59,456,364

Statements of Cash Flows (Unaud

Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net loss	$ (41,146)	$ (36,995)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	158	119
Stock-based compensation	3,687	2,713
Noncash interest expense on loans	530	271
Revaluation of warrant liability	(56)	(70)
Amortization of bond premiums on marketable securities	316	804
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,674)	(1,238)
Accounts payable, accrued expenses and other liabilities	(9,563)	(1,090)
Deferred revenue	0	(3,750)
Net cash used in operating activities	(47,748)	(39,236)
Investing activities:
Purchases of property and equipment	(2,019)	(220)
Maturities of marketable securities	48,443	55,014
Purchases of marketable securities	(32,646)	(37,380)
Net cash provided by investing activities	13,778	17,414
Financing activities:
Proceeds from exercise of common stock options	355	61
Proceeds from issuance of common stock, net	13,687	11,792
Capital lease payments	(3)	(2)
Proceeds from loans payable, net	9,921	0
Net cash provided by financing activities	23,960	11,851
Net decrease in cash and cash equivalents	(10,010)	(9,971)
Cash, cash equivalents and restricted cash—beginning of period	25,459	46,886
Cash, cash equivalents and restricted cash—end of period	15,449	36,915
Supplemental disclosure of cash flow information:
Cash paid for interest	778	602
Capital lease additions	0	9
Fair value of common stock warrants issued	$ 184	$ 0

Organization and Description of

Organization and Description of the Business	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of the Business	Organization and Description of the Business Trevena, Inc., or the Company, was incorporated in Delaware as Parallax Therapeutics, Inc. on November 9, 2007. The Company began operations in December 2007, and its name was changed to Trevena, Inc. on January 3, 2008. The Company is a biopharmaceutical company developing innovative therapies based on breakthrough science to benefit patients and healthcare providers confronting serious medical conditions. The Company operates in one segment and has its principal office in Chesterbrook, Pennsylvania. Liquidity At June 30, 2017 , the Company had an accumulated deficit of $326.8 million . The Company’s net loss was $ 41.1 million and $ 37.0 million for the six months ended June 30, 2017 and 2016 , respectively. The Company expects its cash and cash equivalents of $14.0 million and marketable securities of $70.2 million as of June 30, 2017 , together with interest thereon, to be sufficient to fund its operating expenses and capital expenditure requirements into the third quarter of 2018 .

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. The Company’s functional currency is the U.S. dollar. The financial statements include all normal and recurring adjustments that are considered necessary for the fair presentation of the Company’s balance sheet as of June 30, 2017 , its results of operations and its comprehensive loss for the three and six months ended June 30, 2017 and 2016 , its statement of stockholders’ equity for the period from January 1, 2017 to June 30, 2017 , and its cash flows for the six months ended June 30, 2017 and 2016 . The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and accompanying notes included in the Company’s most recent Annual Report on Form 10-K for the year ended December 31, 2016 . Since the date of those financial statements, there have been no changes to the Company’s significant accounting policies. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2017 and 2016 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 , any other interim periods, or any future year or period. Recent Accounting Standards Not Yet Adopted In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), to clarify how certain cash receipts and payments should be presented in the statement of cash flows. The standard is effective for annual periods beginning after December 15, 2017 and interim periods within that reporting period. Early adoption is permitted. The Company is evaluating the effect this standard will have on its financial statements and related disclosures. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842 ), which requires lessees to record most leases on their balance sheets and disclose key information about leasing arrangements in an effort to increase transparency and comparability among organizations. The standard is effective for annual periods beginning after December 15, 2018 and interim periods within that reporting period. Early adoption is permitted. The Company is evaluating the effect this standard will have on its financial statements and related disclosures. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers . ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to a customer in an amount reflecting the consideration it expects to receive in exchange for those goods or services. Additionally, in March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations . ASU 2016-08 amends the principal versus agent guidance in ASU 2014-09 to clarify how an entity should identify the unit of accounting for the principal versus agent evaluation and how it should apply the control principal to certain types of arrangements. The effective date for both standards is January 1, 2018, with an option that permits companies to adopt the standard as early as the January 1, 2017 . Early application prior to the January 1, 2017 is not permitted. The Company has determined that they will elect the modified retrospective transition method, meaning the cumulative effect of applying the new guidance is recognized at the date of initial application as an adjustment to the opening accumulated deficit balance. Since the Company does not expect to have any open contracts with customers as of December 31, 2017, the adoption of this standard is not expected to have a material impact on the Company's financial statements.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments ASC Topic 820, Fair Value Measurement, establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes among the following: • Level 1-Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. • Level 2-Valuations based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active and models for which all significant inputs are observable, either directly or indirectly. • Level 3-Valuations based on inputs that are unobservable and significant to the overall fair value measurement. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Cash, Cash Equivalents and Marketable Securities The following table presents fair value of the Company’s cash, cash equivalents and marketable securities as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Adjusted Cost Unrealized Gains Unrealized Loss Fair Value Cash and Cash Equivalents Restricted Cash Marketable Securities Cash $ 5,283 $ — $ — $ 5,283 $ 3,870 $ 1,413 $ — Level 1 (1): Money market funds 10,167 — — 10,167 10,167 — — Level 2 (2): U.S. government agency securities 70,222 — (59 ) 70,163 — — 70,163 Total $ 85,672 $ — $ (59 ) $ 85,613 $ 14,037 $ 1,413 $ 70,163 December 31, 2016 Adjusted Cost Unrealized Gains Unrealized Losses Cash and Cash Equivalent Restricted Cash Marketable Securities Fair Value Cash $ 13,756 $ — $ — $ 13,756 $ 12,563 $ 1,193 $ — Level 1 (1): Money market funds 10,043 — — 10,043 10,043 — — Level 2 (2): Cash and cash equivalents 1,660 — — 1,660 1,660 — — U.S. government agency securities 86,333 19 (17 ) 86,335 — — 86,335 Subtotal 87,993 19 (17 ) 87,995 1,660 — 86,335 Total $ 111,792 $ 19 $ (17 ) $ 111,794 $ 24,266 $ 1,193 $ 86,335 ________________ (1) The fair value of Level 1 securities is estimated based on quoted prices in active markets for identical assets or liabilities. (2) The fair value of Level 2 securities is estimated based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company classifies investments available to fund current operations as current assets on its balance sheets. As of June 30, 2017 , the Company did not hold any investment securities exceeding a one-year maturity. Unrealized gains and losses on marketable securities are recorded as a separate component of accumulated other comprehensive income (loss) included in stockholders’ equity. The Company recorded an unrealized loss of $(0.1) million and an unrealized gain of $0.3 million during the six months ended June 30, 2017 and 2016 , respectively. Realized gains (losses) are included in interest income (expense) in the statement of operations and comprehensive income (loss) on a specific identification basis. The Company did not record any realized gains or losses during the six months ended June 30, 2017 and 2016 . To date, the Company has not recorded any impairment charges on marketable securities related to other-than-temporary declines in market value. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers between Level 2 and Level 3 during the six months ended June 30, 2017 or the year ended December 31, 2016 . Warrants At June 30, 2017 , there is an outstanding warrant to purchase up to 20,161 shares of the Company’s common stock with a fair value recorded as a liability as it contains a cash settlement feature upon certain strategic transactions. The following table sets forth a summary of changes in the fair value of this warrant liability, which represents a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs (in thousands): Warrant Liability Balance as of December 31, 2016 $ 75 Amounts acquired or issued — Changes in estimated fair value (56 ) Balance as of June 30, 2017 $ 19 On each re-measurement date, the fair value of the warrant classified as a liability is estimated using the Black-Scholes option pricing model. For this liability, the Company develops its own assumptions that do not have observable inputs or available market data to support the fair value. This method of valuation involves using inputs such as the fair value of the Company’s common stock, stock price volatility, the contractual term of the warrant, risk-free interest rates and dividend yields. Due to the nature of these inputs, the valuation of the warrant is considered a Level 3 measurement. The following assumptions were used at June 30, 2017 and December 31, 2016 to value the warrant liability: June 30, 2017 December 31, 2016 Estimated remaining term 4.9 years 5.3 years Risk-free interest rate 1.8 % 2.0 % Volatility 77.6 % 77.2 % Dividend yield 0 % 0 % Fair value of underlying instrument* $ 2.30 $ 5.88 __________________________________________________ * Trevena, Inc. closing stock price. The warrant liability is recorded on its own line item on the Company’s balance sheets and is marked-to-market at each reporting period with the change in fair value recorded on its own line in the statements of operations and comprehensive loss. In addition to the outstanding warrant to purchase 20,161 shares of common stock discussed above, the Company has outstanding warrants to purchase an aggregate of 102,930 shares of the Company’s common stock. These warrants qualify for equity classification and have been allocated upon the relative fair value of the base instrument and the warrants. See Note 4 for additional information. 3. Fair Value of Financial Instruments ASC Topic 820, Fair Value Measurement, establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes among the following: • Level 1-Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. • Level 2-Valuations based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active and models for which all significant inputs are observable, either directly or indirectly. • Level 3-Valuations based on inputs that are unobservable and significant to the overall fair value measurement. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Cash, Cash Equivalents and Marketable Securities The following table presents fair value of the Company’s cash, cash equivalents and marketable securities as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Adjusted Cost Unrealized Gains Unrealized Loss Fair Value Cash and Cash Equivalents Restricted Cash Marketable Securities Cash $ 5,283 $ — $ — $ 5,283 $ 3,870 $ 1,413 $ — Level 1 (1): Money market funds 10,167 — — 10,167 10,167 — — Level 2 (2): U.S. government agency securities 70,222 — (59 ) 70,163 — — 70,163 Total $ 85,672 $ — $ (59 ) $ 85,613 $ 14,037 $ 1,413 $ 70,163 December 31, 2016 Adjusted Cost Unrealized Gains Unrealized Losses Cash and Cash Equivalent Restricted Cash Marketable Securities Fair Value Cash $ 13,756 $ — $ — $ 13,756 $ 12,563 $ 1,193 $ — Level 1 (1): Money market funds 10,043 — — 10,043 10,043 — — Level 2 (2): Cash and cash equivalents 1,660 — — 1,660 1,660 — — U.S. government agency securities 86,333 19 (17 ) 86,335 — — 86,335 Subtotal 87,993 19 (17 ) 87,995 1,660 — 86,335 Total $ 111,792 $ 19 $ (17 ) $ 111,794 $ 24,266 $ 1,193 $ 86,335 ________________ (1) The fair value of Level 1 securities is estimated based on quoted prices in active markets for identical assets or liabilities. (2) The fair value of Level 2 securities is estimated based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company classifies investments available to fund current operations as current assets on its balance sheets. As of June 30, 2017 , the Company did not hold any investment securities exceeding a one-year maturity. Unrealized gains and losses on marketable securities are recorded as a separate component of accumulated other comprehensive income (loss) included in stockholders’ equity. The Company recorded an unrealized loss of $(0.1) million and an unrealized gain of $0.3 million during the six months ended June 30, 2017 and 2016 , respectively. Realized gains (losses) are included in interest income (expense) in the statement of operations and comprehensive income (loss) on a specific identification basis. The Company did not record any realized gains or losses during the six months ended June 30, 2017 and 2016 . To date, the Company has not recorded any impairment charges on marketable securities related to other-than-temporary declines in market value. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers between Level 2 and Level 3 during the six months ended June 30, 2017 or the year ended December 31, 2016 . Warrants At June 30, 2017 , there is an outstanding warrant to purchase up to 20,161 shares of the Company’s common stock with a fair value recorded as a liability as it contains a cash settlement feature upon certain strategic transactions. The following table sets forth a summary of changes in the fair value of this warrant liability, which represents a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs (in thousands): Warrant Liability Balance as of December 31, 2016 $ 75 Amounts acquired or issued — Changes in estimated fair value (56 ) Balance as of June 30, 2017 $ 19 On each re-measurement date, the fair value of the warrant classified as a liability is estimated using the Black-Scholes option pricing model. For this liability, the Company develops its own assumptions that do not have observable inputs or available market data to support the fair value. This method of valuation involves using inputs such as the fair value of the Company’s common stock, stock price volatility, the contractual term of the warrant, risk-free interest rates and dividend yields. Due to the nature of these inputs, the valuation of the warrant is considered a Level 3 measurement. The following assumptions were used at June 30, 2017 and December 31, 2016 to value the warrant liability: June 30, 2017 December 31, 2016 Estimated remaining term 4.9 years 5.3 years Risk-free interest rate 1.8 % 2.0 % Volatility 77.6 % 77.2 % Dividend yield 0 % 0 % Fair value of underlying instrument* $ 2.30 $ 5.88 __________________________________________________ * Trevena, Inc. closing stock price. The warrant liability is recorded on its own line item on the Company’s balance sheets and is marked-to-market at each reporting period with the change in fair value recorded on its own line in the statements of operations and comprehensive loss. In addition to the outstanding warrant to purchase 20,161 shares of common stock discussed above, the Company has outstanding warrants to purchase an aggregate of 102,930 shares of the Company’s common stock. These warrants qualify for equity classification and have been allocated upon the relative fair value of the base instrument and the warrants. See Note 4 for additional information.

Loans Payable

Loans Payable	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Loans Payable	Loans Payable In September 2014, the Company entered into a loan and security agreement with Oxford Finance LLC and Pacific Western Bank (formerly Square 1Bank) (together, the lenders), pursuant to which the lenders agreed to lend the Company up to $35.0 million in a three -tranche series of term loans (Term Loans A, B, and C). Upon initially entering into the agreement, the Company borrowed $2.0 million under Term Loan A. In April 2015, the Company amended the agreement with the lenders to change the draw period for Term Loan B. In December 2015, the Company further amended the agreement with the lenders to, among other things, change the draw period for Term Loan C, modify the interest only period, and modify the maturity date of the loan. In December 2015, the Company borrowed the Term Loan B tranche of $16.5 million . The Company’s ability to draw an additional $16.5 million under Term Loan C was subject to the satisfaction of one or more specified triggers related to the results of the Company’s Phase 2b clinical trial of TRV027, which were announced in May 2016. Although those triggers were not attained, in December 2016, the Company and the lenders modified the terms and conditions under which the Company could exercise an option to draw $10.0 million of Term Loan C. In March 2017, the Company borrowed the Term Loan C tranche of $10.0 million . Borrowings under Term Loans A and B accrue interest at a fixed rate of 6.50% per annum. Borrowings under Term Loan C accrue interest at a fixed rate of 6.98% per annum. The Company is required to make payments of interest only on borrowings under the loan agreement on a monthly basis through and including January 1, 2018, after which payments of principal in equal monthly installments and accrued interest will be due until the loan matures on March 1, 2020. Upon the last payment date of the amounts borrowed under the agreement, the Company will be required to pay a final payment fee equal to 6.6% of the aggregate amounts borrowed, which is recorded as interest expense over the term of the loans payable. In addition, if the Company repays Term Loan A, Term Loan B, or Term Loan C prior to the applicable maturity date, it will pay the lenders a prepayment fee 2.0% of the total amount prepaid if the prepayment occurs between December 23, 2016 and December 23, 2017, and 1.0% of the total amount prepaid if the prepayment occurs on or after December 24, 2017. The Company’s obligations under the loan and security agreement are secured by a first priority security interest in substantially all of the assets of the Company, other than intellectual property. The Company has agreed not to pledge or otherwise encumber its intellectual property, other than through grants of certain permitted non-exclusive or exclusive licenses or other conveyances of its intellectual property. The loan and security agreement includes affirmative and restrictive covenants, including: (a) financial reporting requirements; (b) limitations on the incurrence of indebtedness; (c) limitations on liens; (d) limitations on certain merger and acquisition transactions; (e) limitations on dispositions of certain assets; (f) limitations on fundamental corporate changes (including changes in control); (g) limitations on investments; (h) limitations on payments and distributions and (i) other covenants. The agreement also contains certain events of default, including for payment defaults, breaches of covenants, a material adverse change in the collateral, the Company’s business, operations or condition (financial or otherwise), certain levies, attachments and other restraints on the Company’s business, insolvency, defaults under other agreements and misrepresentations. In connection with entering into the original agreement, the Company issued to the lenders and the placement agent warrants to purchase an aggregate of 7,678 shares of the Company’s common stock; warrants to purchase an aggregate of 5,728 shares remain outstanding as of June 30, 2017 . These warrants are exercisable immediately and have an exercise price of $5.861 per share. The warrants may be exercised on a cashless basis and will terminate on the earlier of September 19, 2024 or the closing of a merger or consolidation transaction in which the Company is not the surviving entity. In connection with the draw of Term Loan B, the Company issued to the lenders and the placement agent additional warrants to purchase an aggregate of 34,961 shares of the Company’s common stock. These warrants have substantially the same terms as those described above, and have an exercise price of $10.6190 per share and an expiration date of December 23, 2025. In connection with draw of Term Loan C, the Company issued to the lenders and placement agent additional warrants to purchase an aggregate of 62,241 shares of our common stock. These warrants have substantially the same terms as those noted above, and have an exercise price of $3.6150 per share and an expiration date of March 31, 2027. These detachable warrant instruments have qualified for equity classification and have been allocated upon the relative fair value of the base instrument and the warrants, according to the guidance of ASC 470-20-25-2. As of June 30, 2017 , borrowings of $28.5 million attributable to Term Loans A, B, and C remain outstanding. Interest expense of $0.5 million was recorded during each of the six months ended June 30, 2017 and 2016 . The Company incurred lender and third party costs of $0.2 million and $0.1 million , respectively, related to the issuance of Term Loan A. The Company incurred immaterial lender and third party costs related to the issuance of Term Loans B and C. The lender costs are classified as a debt discount and the third party costs are classified as debt issuance costs. Per ASU 2015-3, Interest-Imputation of Interest , debt discount and debt issuance costs are to be presented as a contra-liability to the debt on the balance sheet. These costs will be amortized to interest expense over the life of the loans using the effective interest method. Immaterial amounts of debt discount and debt issuance cost were amortized to interest expense during the six months ended June 30, 2017 and 2016 respectively. The following table summarizes how the issuance of Term Loans A, B, and C are reflected on the balance sheet at June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Gross proceeds $ 28,500 $ 18,500 Debt discount and debt issuance costs (512 ) (191 ) Carrying value 27,988 18,309 Current portion of loans payable, net 7,093 5,039 Loans payable, net $ 20,895 $ 13,270

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Equity Offerings On December 14, 2015, the Company entered into an at the market, or ATM, sales agreement with Cowen and Company, LLC, or Cowen, to offer and sell, from time to time at its sole discretion, shares of its common stock, par value $0.001 per share, having an aggregate offering price of up to $75.0 million through Cowen as its sales agent. Sales of the shares are deemed to be “at the market offerings”, as defined in Rule 415 under the Securities Act of 1933, as amended. The Company is required to pay Cowen a commission of up to three percent of the gross sales proceeds and has provided Cowen with customary indemnification rights. In 2016 , the Company issued and sold 4,815,491 shares of common stock under this ATM facility at a weighted average price per share of $6.865 . The net offering proceeds to the Company were approximately $32.1 million after deducting related expenses, including commissions. In the six months ended June 30, 2017 , the Company issued and sold an additional 3,403,955 shares of common stock under the ATM facility at a weighted average price per share of $4.13 . The net offering proceeds to the Company were approximately $13.7 million after deducting related expenses, including commissions. As of June 30, 2017 , approximately $27.9 million remained available under the ATM facility. Equity Incentive Plans As further described below, we have three share-based compensation plans that authorize the Company to grant various forms of stock options and restricted stock to eligible employees, directors and consultants to the Company. Under all of such plans, the amount, terms of grants and exercisability provisions are determined by the board of directors or its designee. The term of the options may be up to 10 years, and options are exercisable in cash or as otherwise determined by the board of directors. Vesting generally occurs over a period of not greater than 4 years. On December 15, 2016, the Company adopted the Trevena, Inc. Inducement Plan, or the Inducement Plan, which became effective on January 1, 2017. Under the Inducement Plan, the Company reserved 500,000 shares of the Company’s common stock for issuance as nonstatutory stock options and restricted stock unit awards, of which 400,000 shares remain available for issuance as of June 30, 2017 . The only persons eligible to receive grants of awards under the Inducement Plan are individuals who satisfy the standards for inducement grants under NASDAQ Marketplace Rule 5635(c)(4) and the related guidance under Nasdaq IM 5635-1, including individuals who were not previously an employee or director of the Company or are following a bona fide period of non-employment, in each case as an inducement material to such individual’s agreement to enter into employment with the Company. In addition, the Company may grant stock awards under the 2013 Equity Incentive Plan to employees, including officers, non-employee directors and consultants of the Company. The estimated grant-date fair value of the Company’s stock-based awards is amortized ratably over the awards’ service periods. Stock-based compensation expense recognized was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Research and development $ 735 $ 623 $ 1,441 $ 1,129 General and administrative 1,158 887 2,246 1,584 Total stock-based compensation $ 1,893 $ 1,510 $ 3,687 $ 2,713 Options Outstanding Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Balance, December 31, 2016 6,370,578 $ 6.10 7.6 Granted 2,826,844 4.72 Exercised (283,995 ) 1.25 Forfeited/Cancelled (393,275 ) 6.80 Balance, June 30, 2017 8,520,152 $ 5.78 8.02 Vested or expected to vest at June 30, 2017 8,520,152 $ 5.78 8.02 Exercisable at June 30, 2017 3,514,623 $ 5.19 6.58 The intrinsic value of the options exercisable as of June 30, 2017 was $0.7 million , based on the Company’s closing stock price of $2.30 per share and a weighted average exercise price of $5.19 per share. At June 30, 2017 , there was $17.7 million of total unrecognized compensation expense related to unvested options that will be recognized over the weighted average remaining period of 2.90 years. The Company uses the Black-Scholes option pricing model to estimate the fair value of stock options at the grant date. The Black-Scholes model requires the Company to make certain estimates and assumptions, including estimating the fair value of the Company’s common stock, assumptions related to the expected price volatility of the Company’s stock, the period during which the options will be outstanding, the rate of return on risk-free investments and the expected dividend yield for the Company’s common stock. The per-share weighted-average grant date fair value of the options granted to employees and directors during the six months ended June 30, 2017 and 2016 was estimated at $3.20 and $5.34 per share, respectively, on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: Six Months Ended 2017 2016 Expected term of options (in years) 6.2 6.2 Risk-free interest rate 2.1 % 1.5 % Expected volatility 75.7 % 67.9 % Dividend yield 0 % 0 % Shares Available for Future Grant At June 30, 2017 , the Company has the following shares available to be granted under the 2013 Plan and the Inducement Plan: 2013 Plan Inducement Plan Available at December 31, 2016 1,101,331 — Authorized 2,230,736 500,000 Granted (2,726,844 ) (100,000 ) Forfeited/Cancelled 393,275 — Available at June 30, 2017 998,498 400,000 Shares Reserved for Future Issuance At June 30, 2017 , the Company has reserved the following shares of common stock for issuance: Stock options outstanding 8,520,152 Shares available for future grant under 2013 Plan 998,498 Shares available for future grant under Inducement Plan 400,000 Employee stock purchase plan 225,806 Warrants outstanding 123,091 Total shares of common stock reserved for future issuance 10,267,547

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings The Company is not involved in any legal proceeding that it expects to have a material effect on its business, financial condition, results of operations and cash flows.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2017
Revenue Recognition [Abstract]
Revenue	Revenue For arrangements with multiple elements, the Company recognizes revenue in accordance with the FASB’s Accounting Standards Update No. 2009-13, Multiple-Deliverable Revenue Arrangements, which provides guidance for separating and allocating consideration in a multiple element arrangement. Deliverables under the arrangement are separate units of accounting if the delivered item has value to the customer on a standalone basis and if the arrangement includes a general right of return relative to the delivery or performance of the undelivered item is considered probable and substantially within the Company’s control. The consideration that is fixed or determinable at the inception of the arrangement is allocated to the separate units of accounting based on their relative selling prices. Management exercises significant judgment in determining whether a deliverable is a separate unit of accounting. In determining the separate units of accounting, the Company evaluates whether the components have standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangements. Whenever the Company determines that an element is delivered over a period of time, revenue is recognized using either a proportional performance model, if a pattern of performance can be determined, or a straight-line model over the period of performance, which is typically the research and development term. The Company entered into a letter agreement with Allergan plc in March 2015 under which the Company received a nonrefundable upfront fee of $10.0 million . The terms of this agreement contained multiple deliverables which include (i) research and development activities and (ii) testing and analysis related to the Phase 2b trial of TRV027. Collaboration revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or the services have been rendered, and the Company has fulfilled its performance obligations under the contract. The collaboration revenue was recorded on a straight-line basis and was fully recognized as of June 30, 2016 . For the three and six months ended June 30, 2016, the Company recognized collaboration revenue of $1.9 million and $3.8 million , respectively.

Net Loss Per Common Share

Net Loss Per Common Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Net Loss Per Common Share	Net Loss Per Common Share The following table sets forth the computation of basic and diluted net loss per share for the periods indicated (in thousands, except share and per share data): Three Months Ended Six Months Ended 2017 2016 2017 2016 Basic and diluted net loss per common share calculation: Net loss $ (20,432 ) $ (19,216 ) $ (41,146 ) $ (36,995 ) Net loss attributable to common stockholders $ (20,432 ) $ (19,216 ) $ (41,146 ) $ (36,995 ) Weighted average common shares outstanding 58,381,868 52,174,569 57,642,379 51,762,467 Net loss per share of common stock - basic and diluted $ (0.35 ) $ (0.37 ) $ (0.71 ) $ (0.71 ) The following outstanding securities at June 30, 2017 and 2016 have been excluded from the computation of diluted weighted shares outstanding, as they would have been anti-dilutive: June 30, 2017 2016 Options outstanding 8,520,152 6,480,580 Warrants 123,091 60,850 Total 8,643,243 6,541,430

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) The following table presents changes in the components of accumulated other comprehensive income (loss) (in thousands): Balance, December 31, 2016 $ 2 Net unrealized loss on marketable securities (59 ) Balance, June 30, 2017 $ (57 ) There were no reclassifications out of accumulated other comprehensive income (loss) during the six months ended June 30, 2017 and 2016 . There was no tax effect during the three and six months ended June 30, 2017 and 2016 .

Summary of Significant Accoun16

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. The Company’s functional currency is the U.S. dollar. The financial statements include all normal and recurring adjustments that are considered necessary for the fair presentation of the Company’s balance sheet as of June 30, 2017 , its results of operations and its comprehensive loss for the three and six months ended June 30, 2017 and 2016 , its statement of stockholders’ equity for the period from January 1, 2017 to June 30, 2017 , and its cash flows for the six months ended June 30, 2017 and 2016 . The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and accompanying notes included in the Company’s most recent Annual Report on Form 10-K for the year ended December 31, 2016 . Since the date of those financial statements, there have been no changes to the Company’s significant accounting policies. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2017 and 2016 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 , any other interim periods, or any future year or period.
Recent Accounting Standards Not Yet Adopted	Recent Accounting Standards Not Yet Adopted In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), to clarify how certain cash receipts and payments should be presented in the statement of cash flows. The standard is effective for annual periods beginning after December 15, 2017 and interim periods within that reporting period. Early adoption is permitted. The Company is evaluating the effect this standard will have on its financial statements and related disclosures. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842 ), which requires lessees to record most leases on their balance sheets and disclose key information about leasing arrangements in an effort to increase transparency and comparability among organizations. The standard is effective for annual periods beginning after December 15, 2018 and interim periods within that reporting period. Early adoption is permitted. The Company is evaluating the effect this standard will have on its financial statements and related disclosures. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers . ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to a customer in an amount reflecting the consideration it expects to receive in exchange for those goods or services. Additionally, in March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers, Principal versus Agent Considerations . ASU 2016-08 amends the principal versus agent guidance in ASU 2014-09 to clarify how an entity should identify the unit of accounting for the principal versus agent evaluation and how it should apply the control principal to certain types of arrangements. The effective date for both standards is January 1, 2018, with an option that permits companies to adopt the standard as early as the January 1, 2017 . Early application prior to the January 1, 2017 is not permitted.

Fair Value of Financial Instr17

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Schedule of cash and available-for-sale securities’ adjusted cost, gross unrealized gains, gross unrealized losses and fair values by significant investment category	The following table presents fair value of the Company’s cash, cash equivalents and marketable securities as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Adjusted Cost Unrealized Gains Unrealized Loss Fair Value Cash and Cash Equivalents Restricted Cash Marketable Securities Cash $ 5,283 $ — $ — $ 5,283 $ 3,870 $ 1,413 $ — Level 1 (1): Money market funds 10,167 — — 10,167 10,167 — — Level 2 (2): U.S. government agency securities 70,222 — (59 ) 70,163 — — 70,163 Total $ 85,672 $ — $ (59 ) $ 85,613 $ 14,037 $ 1,413 $ 70,163 December 31, 2016 Adjusted Cost Unrealized Gains Unrealized Losses Cash and Cash Equivalent Restricted Cash Marketable Securities Fair Value Cash $ 13,756 $ — $ — $ 13,756 $ 12,563 $ 1,193 $ — Level 1 (1): Money market funds 10,043 — — 10,043 10,043 — — Level 2 (2): Cash and cash equivalents 1,660 — — 1,660 1,660 — — U.S. government agency securities 86,333 19 (17 ) 86,335 — — 86,335 Subtotal 87,993 19 (17 ) 87,995 1,660 — 86,335 Total $ 111,792 $ 19 $ (17 ) $ 111,794 $ 24,266 $ 1,193 $ 86,335 ________________ (1) The fair value of Level 1 securities is estimated based on quoted prices in active markets for identical assets or liabilities. (2) The fair value of Level 2 securities is estimated based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
Schedule of changes in the fair value of the Company's warrant liability representing a recurring measurement classified within Level 3, wherein fair value is estimated using significant unobservable inputs	The following table sets forth a summary of changes in the fair value of this warrant liability, which represents a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs (in thousands): Warrant Liability Balance as of December 31, 2016 $ 75 Amounts acquired or issued — Changes in estimated fair value (56 ) Balance as of June 30, 2017 $ 19
Schedule of assumptions used for valuation of warrants	The following assumptions were used at June 30, 2017 and December 31, 2016 to value the warrant liability: June 30, 2017 December 31, 2016 Estimated remaining term 4.9 years 5.3 years Risk-free interest rate 1.8 % 2.0 % Volatility 77.6 % 77.2 % Dividend yield 0 % 0 % Fair value of underlying instrument* $ 2.30 $ 5.88 __________________________________________________ * Trevena, Inc. closing stock price.

Loans Payable (Tables)

Loans Payable (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Schedule of loans reflected on the balance sheet	The following table summarizes how the issuance of Term Loans A, B, and C are reflected on the balance sheet at June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Gross proceeds $ 28,500 $ 18,500 Debt discount and debt issuance costs (512 ) (191 ) Carrying value 27,988 18,309 Current portion of loans payable, net 7,093 5,039 Loans payable, net $ 20,895 $ 13,270

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of share-based compensation expense recognized	The estimated grant-date fair value of the Company’s stock-based awards is amortized ratably over the awards’ service periods. Stock-based compensation expense recognized was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Research and development $ 735 $ 623 $ 1,441 $ 1,129 General and administrative 1,158 887 2,246 1,584 Total stock-based compensation $ 1,893 $ 1,510 $ 3,687 $ 2,713
Summary of stock option activity	Options Outstanding Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Balance, December 31, 2016 6,370,578 $ 6.10 7.6 Granted 2,826,844 4.72 Exercised (283,995 ) 1.25 Forfeited/Cancelled (393,275 ) 6.80 Balance, June 30, 2017 8,520,152 $ 5.78 8.02 Vested or expected to vest at June 30, 2017 8,520,152 $ 5.78 8.02 Exercisable at June 30, 2017 3,514,623 $ 5.19 6.58
Schedule of weighted-average assumptions:	The per-share weighted-average grant date fair value of the options granted to employees and directors during the six months ended June 30, 2017 and 2016 was estimated at $3.20 and $5.34 per share, respectively, on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: Six Months Ended 2017 2016 Expected term of options (in years) 6.2 6.2 Risk-free interest rate 2.1 % 1.5 % Expected volatility 75.7 % 67.9 % Dividend yield 0 % 0 %
Schedule of shares of common stock reserved/available	At June 30, 2017 , the Company has reserved the following shares of common stock for issuance: Stock options outstanding 8,520,152 Shares available for future grant under 2013 Plan 998,498 Shares available for future grant under Inducement Plan 400,000 Employee stock purchase plan 225,806 Warrants outstanding 123,091 Total shares of common stock reserved for future issuance 10,267,547 At June 30, 2017 , the Company has the following shares available to be granted under the 2013 Plan and the Inducement Plan: 2013 Plan Inducement Plan Available at December 31, 2016 1,101,331 — Authorized 2,230,736 500,000 Granted (2,726,844 ) (100,000 ) Forfeited/Cancelled 393,275 — Available at June 30, 2017 998,498 400,000

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted net loss per share	The following table sets forth the computation of basic and diluted net loss per share for the periods indicated (in thousands, except share and per share data): Three Months Ended Six Months Ended 2017 2016 2017 2016 Basic and diluted net loss per common share calculation: Net loss $ (20,432 ) $ (19,216 ) $ (41,146 ) $ (36,995 ) Net loss attributable to common stockholders $ (20,432 ) $ (19,216 ) $ (41,146 ) $ (36,995 ) Weighted average common shares outstanding 58,381,868 52,174,569 57,642,379 51,762,467 Net loss per share of common stock - basic and diluted $ (0.35 ) $ (0.37 ) $ (0.71 ) $ (0.71 )
Schedule of outstanding securities excluded from the computation of diluted weighted shares outstanding as they would have been anti-dilutive	The following outstanding securities at June 30, 2017 and 2016 have been excluded from the computation of diluted weighted shares outstanding, as they would have been anti-dilutive: June 30, 2017 2016 Options outstanding 8,520,152 6,480,580 Warrants 123,091 60,850 Total 8,643,243 6,541,430

Other Comprehensive Income (L21

Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Schedule of accumulated other comprehensive income (loss), net of tax	The following table presents changes in the components of accumulated other comprehensive income (loss) (in thousands): Balance, December 31, 2016 $ 2 Net unrealized loss on marketable securities (59 ) Balance, June 30, 2017 $ (57 )

Organization and Description 22

Organization and Description of the Business (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)segment	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | segment			1
Liquidity
Accumulated deficit	$ 326,771		$ 326,771		$ 285,625
Net loss	20,432	$ 19,216	41,146	$ 36,995
Cash and cash equivalents	14,037		14,037		24,266
Marketable securities	$ 70,163		$ 70,163		$ 86,335

Fair Value of Financial Instr23

Fair Value of Financial Instruments - Hierarchy Table (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair value
Unrealized gain (loss) on marketable securities	$ (8,000)	$ 45,000	$ (59,000)	$ 281,000
Transfers into Level 3			0		$ 0
Transfers out of Level 3			0		0
Restricted cash
Fair value
Fair Value	1,413,000		1,413,000		1,193,000
Total
Fair value
Adjusted Cost	85,672,000		85,672,000		111,792,000
Unrealized Gains	0		0		19,000
Unrealized Losses	(59,000)		(59,000)		(17,000)
Fair Value	85,613,000		85,613,000		111,794,000
Total | Cash and cash equivalents
Fair value
Fair Value	14,037,000		14,037,000		24,266,000
Total | Restricted cash
Fair value
Fair Value	1,413,000		1,413,000		1,193,000
Total | Marketable Securities.
Fair value
Fair Value	70,163,000		70,163,000		86,335,000
Cash
Fair value
Adjusted Cost	5,283,000		5,283,000		13,756,000
Fair Value	5,283,000		5,283,000		13,756,000
Cash | Cash and cash equivalents
Fair value
Fair Value	3,870,000		3,870,000		12,563,000
Level 1 | Money market mutual funds
Fair value
Adjusted Cost	10,167,000		10,167,000		10,043,000
Fair Value	10,167,000		10,167,000		10,043,000
Level 1 | Money market mutual funds | Cash and cash equivalents
Fair value
Fair Value	10,167,000		10,167,000		10,043,000
Level 2
Fair value
Adjusted Cost					87,993,000
Unrealized Gains					19,000
Unrealized Losses					(17,000)
Fair Value					87,995,000
Level 2 | Cash and cash equivalents
Fair value
Fair Value					1,660,000
Level 2 | Marketable Securities.
Fair value
Fair Value					86,335,000
Level 2 | Cash and cash equivalents
Fair value
Adjusted Cost					1,660,000
Fair Value					1,660,000
Level 2 | U.S. government agency securities
Fair value
Adjusted Cost	70,222,000		70,222,000		86,333,000
Unrealized Gains					19,000
Unrealized Losses	(59,000)		(59,000)		(17,000)
Fair Value	70,163,000		70,163,000		86,335,000
Level 2 | U.S. government agency securities | Marketable Securities.
Fair value
Fair Value	$ 70,163,000		$ 70,163,000		$ 86,335,000

Fair Value of Financial Instr24

Fair Value of Financial Instruments - Warrants (Details)	Jun. 30, 2017shares
Common Stock | Warrants | Maximum
Warrants
Number of shares that can be purchased upon exercise of warrants (in shares)	20,161

Fair Value of Financial Instr25

Fair Value of Financial Instruments - Summary of Changes in Warrant Liability (Details) - Warrants - Warrant Liability $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of December 31, 2016	$ 75
Amounts acquired or issued	0
Changes in estimated fair value	(56)
Balance as of June 30, 2017	$ 19

Fair Value of Financial Instr26

Fair Value of Financial Instruments - Warrant Liability Assumptions (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Term Loans A, B and C | Warrants
Warrants
Number of shares that can be purchased upon exercise of warrants (in shares)	102,930
Level 3 | Warrants
Fair value assumptions
Estimated remaining term (in years)	4 years 10 months 30 days	5 years 3 months 18 days
Risk-free interest rate (as a percent)	1.80%	2.00%
Volatility (as a percent)	77.60%	77.20%
Dividend yield (as a percent)	0.00%	0.00%
Fair value of underlying instrument (in dollars per share)	$ 2.30	$ 5.88

Loans Payable - Narrative (Deta

Loans Payable - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)$ / sharesshares	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)$ / sharesshares	Jun. 30, 2016USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)$ / sharesshares	Sep. 30, 2014USD ($)tranche$ / sharesshares
Warrants
Interest expense	$ 731,000	$ 433,000	$ 1,309,000	$ 873,000
Loan and security agreement
Debt Instrument [Line Items]
Face amount								$ 35,000,000
Debt number of tranches | tranche								3
Term Loans A, B and C
Fees
Final payment fee due upon that last payment date of the amounts borrowed under the agreement subject to adjustment (as a percent)			6.60%
Prepayment fee as a percent of total amount prepaid if prepayment occurs between the first and second anniversary of the funding			2.00%
Prepayment fee as a percent of total amount prepaid if prepayment occurs on or after the second anniversary of the funding			1.00%
Warrants
Gross proceeds	$ 28,500,000		$ 28,500,000			$ 18,500,000
Interest expense			$ 500,000	$ 500,000
Term Loans A and B
Debt Instrument [Line Items]
Interest rate (as a percent)	6.50%		6.50%
Term Loan A
Debt Instrument [Line Items]
Face amount								$ 2,000,000
Warrants
Debt discount								200,000
Deferred financing fees								$ 100,000
Term Loan B
Debt Instrument [Line Items]
Face amount							$ 16,500,000
Term Loan C
Debt Instrument [Line Items]
Face amount					$ 10	$ 10
Debt borrowing capacity							$ 16,500,000
Interest rate (as a percent)	6.98%		6.98%
Warrants | Term Loans A, B and C
Warrants
Number of shares that can be purchased upon exercise of warrants (in shares) | shares	102,930		102,930
Warrants | Common Stock | Term Loan A
Warrants
Exercise price (in dollars per share) | $ / shares								$ 5.861
Number of shares that can be purchased upon exercise of warrants (in shares) | shares	5,728		5,728					7,678
Warrants | Common Stock | Term Loan B
Warrants
Exercise price (in dollars per share) | $ / shares							$ 10.6190
Number of shares that can be purchased upon exercise of warrants (in shares) | shares							34,961
Warrants | Common Stock | Term Loan C
Warrants
Exercise price (in dollars per share) | $ / shares	$ 3.6150		$ 3.6150
Number of shares that can be purchased upon exercise of warrants (in shares) | shares	62,241		62,241

Loans Payable - Schedule of Deb

Loans Payable - Schedule of Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Carrying value	$ 20,895	$ 13,270
Current portion of loans payable, net	7,093	5,039
Term Loans A, B and C
Debt Instrument [Line Items]
Gross proceeds	28,500	18,500
Debt discount and debt issuance costs	(512)	(191)
Carrying value	27,988	18,309
Current portion of loans payable, net	7,093	5,039
Loans payable, net	$ 20,895	$ 13,270

Stockholders' Equity - Equity O

Stockholders' Equity - Equity Offerings (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 14, 2015	Jun. 30, 2017	Dec. 31, 2016
Equity Offerings
Common stock, shares authorized (in shares)		100,000,000	100,000,000
Preferred stock, shares authorized (in shares)		5,000,000	5,000,000
Common stock, par value (in dollars per share)		$ 0.001	$ 0.001
Issuance of common stock, net of issuance costs		$ 13,687
Maximum
Equity Offerings
Common stock, par value (in dollars per share)	$ 0.001
At Market Sales Facility
Equity Offerings
Issuance of common stock, net of issuance costs (in shares)		3,403,955	4,815,491
Issuance of common stock, net of issuance costs		$ 13,700	$ 32,100
Remaining amount available		$ 27,900
At Market Sales Facility | Maximum
Equity Offerings
Offering price	$ 75,000
Commission (as percent)	3.00%
At Market Sales Facility | Weighted-average
Equity Offerings
Offering price (in dollars per share)		$ 4.13	$ 6.865
2013 plan
Equity Offerings
Number of shares available for grant (in shares)		998,498	1,101,331
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		2,230,736
Share Based Compensation Arrangement by Share Based Payment Award Decrease In Shares Available for Grant Due to Options Granted		(2,726,844)
Share Based Compensation Arrangement by Share Based Payment Award Decrease In Shares Available for Grant Due to Options Forfeited		393,275
Inducement Plan
Equity Offerings
Number of shares available for grant (in shares)		400,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		500,000
Share Based Compensation Arrangement by Share Based Payment Award Decrease In Shares Available for Grant Due to Options Granted		(100,000)
Share Based Compensation Arrangement by Share Based Payment Award Decrease In Shares Available for Grant Due to Options Forfeited		0

Stockholders' Equity - Equity I

Stockholders' Equity - Equity Incentive Plans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 15, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation			$ 1,893	$ 1,510	$ 3,687	$ 2,713
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation			735	623	1,441	1,129
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation			$ 1,158	$ 887	$ 2,246	$ 1,584
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award (in years)					10 years
Vesting period (in years)					4 years
Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares authorized for issuance (in shares)	400,000	500,000

Stockholders' Equity - Options

Stockholders' Equity - Options Outstanding (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Number of Shares
Balance at the beginning of the period (in shares)	6,370,578
Granted (in shares)	2,826,844
Exercised (in shares)	(283,995)
Forfeited/Cancelled (in shares)	(393,275)
Balance at the end of the period (in shares)	8,520,152	6,370,578
Vested or expected to vest at the end of the period (in shares)	8,520,152
Exercisable at the end of the period (in shares)	3,514,623
Weighted-Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 6.10
Granted (in dollars per share)	4.72
Exercised (in dollars per share)	1.25
Forfeitures/Expirations (in dollars per share)	6.80
Balance at the end of the period (in dollars per share)	5.78	$ 6.10
Vested or expected to vest at the end of the period (in dollars per share)	5.78
Exercisable at the end of the period (in dollars per share)	$ 5.19
Weighted Average Remaining Contractual Term
Options Outstanding at the end of the period	8 years 7 days	7 years 7 months 6 days
Vested or expected to vest at the end of the period	8 years 7 days
Exercisable at the end of the period	6 years 6 months 29 days

Stockholder's Equity - Shares A

Stockholder's Equity - Shares Available for Future Issuance (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercisable			$ 0.7
Weighted average exercise price (in dollars per share)			$ 5.19
Shares Reserved for Future Issuance
Stock options outstanding (in shares)			8,520,152	6,370,578
Employee stock purchase plan (in shares)			225,806
Warrants outstanding (in shares)			123,091
Total shares of common stock reserved for issuance (in shares)			10,267,547
2013 plan
Shares Available for Future Grant
Balance at the beginning of the period (in shares)	1,101,331
Authorized (in shares)			2,230,736
Granted (in shares)	(2,726,844)
Forfeitures/Cancelled (in shares)	393,275
Balance at the end of the period (in shares)	998,498
Shares Reserved for Future Issuance
Shares available for future grant (in shares)	1,101,331		998,498	1,101,331
Inducement Plan
Shares Available for Future Grant
Balance at the beginning of the period (in shares)	0
Authorized (in shares)			500,000
Granted (in shares)	(100,000)
Forfeitures/Cancelled (in shares)	0
Balance at the end of the period (in shares)	400,000
Shares Reserved for Future Issuance
Shares available for future grant (in shares)	0		400,000	0
Options outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per share price of Company's closing stock price (in dollars per share)			$ 2.30
Unrecognized compensation expense			$ 17.7
Weighted average remaining period for recognition of unrecognized compensation expense (in years)	2 years 10 months 24 days
Per-share weighted-average grant date fair value of options granted (in dollars per share)	$ 3.20	$ 5.34
Options outstanding | Weighted-average
Weighted-average assumptions:
Expected term of options (in years)	6 years 2 months 12 days	6 years 2 months 12 days
Risk-free interest rate (as a percent)	2.10%	1.50%
Expected volatility (as a percent)	75.70%	67.90%
Dividend yield (as a percent)	0.00%	0.00%

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenue
Collaboration revenue		$ 0	$ 1,875	$ 0	$ 3,750
Allergan
Revenue
Collaboration revenue			$ 1,900	$ 1,900	$ 3,800
Nonrefundable upfront fee	$ 10,000

Net Loss Per Common Share (Deta

Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Basic and diluted net loss per common share calculation:
Net loss	$ (20,432)	$ (19,216)	$ (41,146)	$ (36,995)
Net loss attributable to common stockholders	$ (20,432)	$ (19,216)	$ (41,146)	$ (36,995)
Weighted average common shares outstanding (in shares)	58,381,868	52,174,569	57,642,379	51,762,467
Net loss per share of common stock—basic and diluted (in dollars per share)	$ (0.35)	$ (0.37)	$ (0.71)	$ (0.71)
Outstanding securities excluded from computation of diluted weighted shares outstanding as they would have been anti dilutive:
Outstanding securities excluded from computation of diluted weighted shares outstanding (in shares)			8,643,243	6,541,430
Options outstanding
Outstanding securities excluded from computation of diluted weighted shares outstanding as they would have been anti dilutive:
Outstanding securities excluded from computation of diluted weighted shares outstanding (in shares)			8,520,152	6,480,580
Warrants
Outstanding securities excluded from computation of diluted weighted shares outstanding as they would have been anti dilutive:
Outstanding securities excluded from computation of diluted weighted shares outstanding (in shares)			123,091	60,850

Other Comprehensive Income (L35

Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax.
Balance, beginning of period			$ 78,581,000
Balance, end of period	$ 55,606,000		55,606,000
Reclassifications out of accumulated other comprehensive income or loss, net of tax			0	$ 0
Tax effect	0	$ 0	0	$ 0
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax.
Balance, beginning of period			2,000
Net unrealized loss on marketable securities			(59,000)
Balance, end of period	$ (57,000)		$ (57,000)