Cara Therapeutics (CARA) 10-Q 4 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 28, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	CARA
Entity Registrant Name	Cara Therapeutics, Inc.
Entity Central Index Key	1,346,830
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		32,507,487

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 5,306	$ 12,092
Marketable securities	31,504	46,184
Income tax receivable	558	852
Other receivables	984	87
Prepaid expenses	1,979	1,530
Restricted cash, current	700	700
Total current assets	41,031	61,445
Property and equipment, net	1,499	1,614
Restricted cash	769	769
Total assets	43,299	63,828
Current liabilities:
Accounts payable and accrued expenses	12,512	11,533
Total current liabilities	12,512	11,533
Deferred lease obligation	1,518	1,570
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock; $0.001 par value; 5,000,000 shares authorized at March 31, 2017 and December 31, 2016, zero shares issued and outstanding at March 31, 2017 and December 31, 2016
Common stock; $0.001 par value; 100,000,000 shares authorized at March 31, 2017 and December 31, 2016, 27,324,154 shares and 27,296,863 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	27	27
Common stock subscribed in follow-on offering; $0.001 par value; 5,117,500 shares at March 31, 2017	5
Additional paid-in capital	300,151	212,866
Subscriptions receivable	(86,518)
Accumulated deficit	(184,420)	(162,171)
Accumulated other comprehensive income	24	3
Total stockholders' equity	29,269	50,725
Total liabilities and stockholders' equity	$ 43,299	$ 63,828

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	27,324,154	27,296,863
Common stock, shares outstanding	27,324,154	27,296,863
Common stock, par value	$ 0.001	$ 0.001
Common stock subscribed in follow-on offering, Shares	5,117,500

Condensed Statements of Compreh

Condensed Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenue:
License and milestone fees	$ 530
Collaborative revenue	313
Clinical compound revenue	68	$ 7
Total revenue	911	7
Operating expenses:
Research and development	20,836	8,546
General and administrative	2,400	2,447
Total operating expenses	23,236	10,993
Operating loss	(22,325)	(10,986)
Other income	90	149
Loss before benefit from income taxes	(22,235)	(10,837)
Benefit from income taxes	31	145
Net loss	$ (22,204)	$ (10,692)
Net loss per share:
Basic and Diluted	$ (0.81)	$ (0.39)
Weighted average shares:
Basic and Diluted	27,299,678	27,259,589
Other comprehensive income (loss), net of tax of $0:
Change in unrealized gains on available-for-sale marketable securities	$ 21	$ 39
Total comprehensive loss	$ (22,183)	$ (10,653)

Condensed Statements of Compre5

Condensed Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Other comprehensive income (loss), tax	$ 0	$ 0

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Common Stock [Member]Follow-on Public Offering [Member]	Additional Paid-In Capital [Member]	Subscriptions Receivable [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, Value at Dec. 31, 2015	$ 105,044	$ 27		$ 209,943		$ (104,891)	$ (35)
Balance, Shares at Dec. 31, 2015		27,254,863
Stock-based compensation expense	496			496
Shares issued upon exercise of stock options, Value	40			40
Shares issued upon exercise of stock options, Shares		28,000
Net loss	(10,692)					(10,692)
Other comprehensive income	39						39
Balance, Value at Mar. 31, 2016	94,927	$ 27		210,479		(115,583)	4
Balance, Shares at Mar. 31, 2016		27,282,863
Balance, Value at Dec. 31, 2016	50,725	$ 27		212,866		(162,171)	3
Balance, Shares at Dec. 31, 2016		27,296,863
Subscription of common stock, net of underwriting discounts and commissions and offering expenses, Value	(530)		$ 5	85,983	$ (86,518)
Subscription of common stock, net of underwriting discounts and commissions and offering expenses, Shares			5,117,500
Stock-based compensation expense	1,108			1,108
Shares issued upon exercise of stock options, Value	149			149
Shares issued upon exercise of stock options, Shares		27,291	0
Net loss	(22,204)					(22,204)
Other comprehensive income	21						21
Balance, Value at Mar. 31, 2017	$ 29,269	$ 27	$ 5	300,151	$ (86,518)	(184,420)	$ 24
Balance, Shares at Mar. 31, 2017		27,324,154	5,117,500
Cumulative effect adjustment upon adoption of ASU 2016-09				$ 45		$ (45)

Condensed Statements of Stockh7

Condensed Statements of Stockholders' Equity (Parenthetical) - Follow-on Public Offering [Member] - Common Stock [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)$ / shares
Sale of common stock, per share | $ / shares	$ 18
Underwriting discounts and commissions and offering expenses | $	$ 6,127

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net loss	$ (22,204)	$ (10,692)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,108	496
Depreciation and amortization	122	730
Amortization/accretion of available-for-sale marketable securities	(4)	(67)
Realized gain on sale of available-for-sale marketable securities	(3)
Deferred rent costs	(52)	(83)
Changes in operating assets and liabilities:
Income tax receivable	294	(145)
Other receivables	(896)	(48)
Prepaid expenses	(449)	(844)
Accounts payable and accrued expenses	448	820
Net cash used in operating activities	(21,636)	(9,833)
Investing activities
Proceeds from maturities of available-for-sale marketable securities	16,156	26,050
Proceeds from sale of available-for-sale marketable securities	5,030
Purchase of available-for-sale marketable securities	(6,477)	(22,625)
Change in restricted cash		(769)
Cash paid for construction in progress		(34)
Purchases of property and equipment	(8)	(8)
Net cash provided by investing activities	14,701	2,614
Financing activities
Proceeds from the exercise of stock options	149	40
Net cash provided by financing activities	149	40
Net cash decrease for the period	(6,786)	(7,179)
Cash and cash equivalents at beginning of period	12,092	15,101
Cash and cash equivalents at end of period	5,306	7,922
Noncash investing and financing activities
Tenant improvements paid by landlord		$ 495
Subscriptions receivable	$ 530

Business

Business	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business	1. Business Cara Therapeutics, Inc. (the “Company”, “we”, “our” or “us”) is a clinical-stage biopharmaceutical corporation formed on July 2, 2004. The Company is focused on developing and commercializing new chemical entities designed to alleviate pain and pruritus by selectively targeting peripheral kappa opioid receptors. The Company’s primary activities to date have been organizing and staffing the company, developing its product candidates, including conducting preclinical studies and clinical trials of CR845-based product candidates and raising capital. As of March 31, 2017, the Company has raised aggregate net proceeds of approximately $204,800 from several rounds of equity financing, including its initial public offering, which closed in February 2014 and its first follow-on offering of common stock, which closed in August 2015, and the issuance of debt. In addition, the Company received approximately $33,500 under its license agreements for CR845, primarily with Maruishi Pharmaceutical Co. Ltd., or Maruishi, and Chong Kun Dang Pharmaceutical Corp., or CKD, and an earlier product candidate for which development efforts ceased in 2007 (see Note 10, Collaborations On April 5, 2017, the Company completed its second follow-on offering, raising aggregate net proceeds of approximately $86,518, net of underwriting discounts and commissions but before deducting estimated offering expenses payable by the Company. The offering was conducted pursuant to a shelf registration statement on Form S-3, which was filed on March 13, 2017 and declared effective by the Securities and Exchange Commission, or the SEC, on March 24, 2017 (see Note 9, Stockholders’ Equity As of March 31, 2017, the Company had unrestricted cash and cash equivalents and marketable securities of $36,810 and an accumulated deficit of $184,420. The Company has incurred substantial net losses and negative cash flows from operating activities in nearly every fiscal period since inception and expects this trend to continue for the foreseeable future. The Company recognized net losses of $22,204 and $10,692 and had net cash used in operating activities of $21,636 and $9,833 for the three months ended March 31, 2017 and 2016, respectively. The Company is subject to risks common to other life science companies including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, product liability protection of proprietary technology, ability to raise additional financing, and compliance with Food and Drug Administration, or FDA, and other government regulations. If the Company does not successfully commercialize any of its product candidates, it will be unable to generate recurring product revenue or achieve profitability.

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	2. Basis of Presentation The unaudited interim condensed financial statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, they do not include all information and disclosures necessary for a presentation of the Company’s financial position, results of operations and cash flows in conformity with generally accepted accounting principles in the United States of America, or GAAP. In the opinion of management, these unaudited interim financial statements reflect all adjustments, consisting primarily of normal recurring accruals, necessary for a fair presentation of results for the periods presented. The results of operations for interim periods are not necessarily indicative of the results for the full year. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted from this report, as is permitted by SEC rules and regulations; however, the Company believes that the disclosures are adequate to make the information presented not misleading. The condensed balance sheet data for the year ended December 31, 2016 were derived from audited financial statements, but do not include all disclosures required by GAAP. These unaudited interim condensed financial statements should be read in conjunction with the audited financial statements and accompanying notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. Use of Estimates The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from the Company’s estimates and assumptions. Significant estimates include the fair value of marketable securities that are classified as level 2 of the fair value hierarchy, useful lives of fixed assets, the periods over which certain revenues will be recognized, including licensing and collaborative revenue recognized from non-refundable up-front and milestone payments, the determination of prepaid research and development, or R&D, clinical costs and accrued research projects, the amount of non-cash compensation costs related to share-based payments to employees and non-employees and the periods over which those costs are expensed and the likelihood of realization of deferred tax assets. Significant Accounting Policies There have been no material changes to the significant accounting policies previously disclosed in Note 2 to the Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. Accounting Pronouncements Recently Adopted As of January 1, 2017, the Company adopted Accounting Standards Update, or ASU, No. 2016-09, Improvements to Employee Share-Based Payment Accounting Topic 718 Compensation – Stock Compensation Recent Accounting Pronouncements Not Yet Adopted In January 2017, the Financial Accounting Standards Board issued ASU No. 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business, ,

Available-for-Sale Marketable S

Available-for-Sale Marketable Securities	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Available-for-Sale Marketable Securities	3. Available-for-Sale Marketable Securities As of March 31, 2017 and December 31, 2016, the Company’s available-for-sale marketable securities consisted of money market funds and debt securities issued by the U.S. government and government-sponsored entities and by investment grade institutions. The following tables summarize the Company’s available-for-sale marketable securities by major type of security as of March 31, 2017 and December 31, 2016: As of March 31, 2017 Gross Unrealized Estimated Fair Value Type of Security Amortized Cost Gains Losses Money market funds $ 7,231 $ 28 $ — $ 7,259 U.S. Treasury securities 2,512 — (2 ) 2,510 U.S. government agency obligations 1,500 — — 1,500 Corporate bonds 11,005 1 (3 ) 11,003 Commercial paper 9,232 — — 9,232 Total available-for-sale marketable securities $ 31,480 $ 29 $ (5 ) $ 31,504 As of December 31, 2016 Gross Unrealized Estimated Type of Security Amortized Cost Gains Losses Money market funds $ 8,268 $ 8 $ — $ 8,276 U.S. Treasury securities 2,523 — (1 ) 2,522 U.S. government agency obligations 3,501 1 — 3,502 Corporate bonds 16,683 — (6 ) 16,677 Commercial paper 15,206 3 (2 ) 15,207 Total available-for-sale marketable securities $ 46,181 $ 12 $ (9 ) $ 46,184 All available-for-sale marketable securities are classified in the Company’s Condensed Balance Sheets as Marketable securities. The Company classifies its marketable debt securities based on their contractual maturity dates. As of March 31, 2017, the Company’s marketable debt securities mature at various dates through August 2017. The fair values and amortized cost of marketable debt securities by contractual maturity were as follows. The table does not include money market funds that are classified as available-for-sale marketable securities. As of March 31, 2017 As of December 31, 2016 Contractual maturity Amortized Cost Fair Value Amortized Cost Fair Value Less than one year $ 24,249 $ 24,245 $ 37,913 $ 37,908 During the three months ended March 31, 2017, the Company sold shares of two investments in commercial paper before their respective maturity dates and shares in a money market fund with a total fair value of $5,030 that were all classified as available-for-sale marketable securities. The cost of the shares of commercial paper and the money market fund that were sold was determined by specific identification. The sales of the investments in commercial paper as well as the sale of the shares of the money market fund each resulted in realized gains, totaling $3. The following tables show the fair value of the Company’s available-for-sale marketable securities that have unrealized losses and that are deemed to be only temporarily impaired, aggregated by investment category and length of time that the individual investments have been in a continuous unrealized loss position. As of March 31, 2017 Less than 12 Months 12 Months or Greater Total Fair Value Gross Fair Value Gross Fair Value Gross U.S. Treasury securities $ 2,510 $ (2 ) $ — $ — $ 2,510 $ (2 ) Corporate bonds 7,751 (3 ) — — 7,751 (3 ) Total $ 10,261 $ (5 ) $ — $ — $ 10,261 $ (5 ) As of December 31, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Gross Fair Value Gross Fair Value Gross U.S. Treasury securities $ 2,522 $ (1 ) $ — $ — $ 2,522 $ (1 ) Corporate bonds 9,919 (6 ) — — 9,919 (6 ) Commercial paper 5,227 (2 ) — — 5,227 (2 ) Total $ 17,668 $ (9 ) $ — $ — $ 17,668 $ (9 ) As of March 31, 2017 and December 31, 2016, the Company held a total of 16 out of 24 positions and 18 out of 34 positions, respectively, that were in an unrealized loss position, none of which had been in an unrealized loss position for 12 months or greater. Based on the Company’s review of these securities, the Company believes that the cost basis of its available-for-sale marketable securities is recoverable and that, therefore, it had no other-than-temporary impairments on these securities as of March 31, 2017 and December 31, 2016. The Company does not intend to sell these debt securities and the Company believes it is not more likely than not that it will be required to sell these securities before the recovery of their amortized cost basis, which may be maturity.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	4. Accumulated Other Comprehensive Income (Loss) The following table summarizes the changes in accumulated other comprehensive income (loss), or AOCI, net of tax, from unrealized gains (losses) on available-for-sale marketable securities, the Company’s only component of AOCI, for the three months ended March 31, 2017 and March 31, 2016. Total Accumulated Balance, December 31, 2016 $ 3 Other comprehensive income before reclassifications 24 Amount reclassified from accumulated other comprehensive income (3 ) Net current period other comprehensive income 21 Balance, March 31, 2017 $ 24 Balance, December 31, 2015 $ (35 ) Other comprehensive income before reclassifications 39 Amount reclassified from accumulated other comprehensive income — Net current period other comprehensive income 39 Balance, March 31, 2016 $ 4 The reclassifications out of AOCI and into net loss were as follows: Three Months Affected Line Item in Component of AOCI 2017 2016 Unrealized gains (losses) on available-for-sale marketable securities $ 3 $ — Other income — — Income tax benefit $ 3 $ — Net of tax The amount reclassified out of AOCI into net loss was determined by specific identification.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements As of March 31, 2017 and December 31, 2016, the Company’s financial instruments consist of cash and cash equivalents, available-for-sale marketable securities, restricted cash, accounts payable and accrued liabilities. The fair values of cash and cash equivalents, restricted cash, accounts payable and accrued liabilities approximate their carrying values due to the short-term nature of these financial instruments. Marketable securities are reported on the Company’s Condensed Balance Sheets at their fair values, based upon pricing of securities with the same or similar investment characteristics as provided by third-party pricing services, as described below. Current accounting guidance defines fair value, establishes a framework for measuring fair value in accordance with ASC section 820, and requires certain disclosures about fair value measurements. The valuation techniques included in the guidance are based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs 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. The Company classifies its investments in a fair value hierarchy that is intended to increase consistency and comparability in fair value measurements and related disclosures. The fair value hierarchy is divided into three levels based on the source of inputs as follows: • Level 1 – Observable inputs – quoted prices in active markets for identical assets and liabilities. • Level 2 – Observable inputs other than the quoted prices in active markets for identical assets and liabilities – such as quoted prices for similar instruments, quoted prices for identical or similar instruments in inactive markets, or other inputs that are observable or can be corroborated by observable market data. • Level 3 – Unobservable inputs – includes amounts derived from valuation models where one or more significant inputs are unobservable and require the Company to develop relevant assumptions. Valuation Techniques - Level 2 Inputs The Company estimates the fair values of its financial instruments categorized as level 2 in the fair value hierarchy, including U.S. Treasury securities, U.S. government agency obligations, corporate bonds, commercial paper and money market funds with similar underlying investments, by taking into consideration valuations obtained from third-party pricing services. The pricing services use industry standard valuation models, including both income- and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, benchmark yields, issuer credit spreads, benchmark securities, and other observable inputs. The Company obtains a single price for each financial instrument and does not adjust the prices obtained from the pricing service. The Company validates the prices provided by its third-party pricing services by reviewing their pricing methods, obtaining market values from other pricing sources and comparing them to the share prices presented by the third-party pricing services. After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by its third-party pricing services as of March 31, 2017 or December 31, 2016. The following tables summarize the Company’s financial assets measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016. Fair value measurement as of March 31, 2017: Financial assets Quoted prices in Significant other Significant active markets for observable unobservable identical assets inputs inputs Type of Instrument Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents: Money market fund and checking accounts $ 5,306 $ 5,306 $ — $ — Available-for-sale marketable securities: Money market funds 7,259 — 7,259 — U.S. Treasury securities 2,510 — 2,510 — U.S. government agency obligations 1,500 — 1,500 — Corporate bonds 11,003 — 11,003 — Commercial paper 9,232 — 9,232 — Restricted cash: Commercial money market account 1,469 1,469 — — Total financial assets $ 38,279 $ 6,775 $ 31,504 $ — Fair value measurement as of December 31, 2016: Financial assets Quoted prices in Significant other Significant active markets for observable unobservable identical assets inputs inputs Type of Instrument Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents: Money market fund and checking accounts $ 12,092 $ 12,092 $ — $ — Available-for-sale marketable securities: Money market fund 8,276 — 8,276 — U.S. Treasury securities 2,522 — 2,522 — U.S. government agency obligations 3,502 — 3,502 — Corporate bonds 16,677 — 16,677 — Commercial paper 15,207 — 15,207 — Restricted cash: Money market fund 1,469 1,469 — — Total financial assets $ 59,745 $ 13,561 $ 46,184 $ — There were no purchases, sales or maturities of Level 3 financial assets and no unrealized gains or losses related to Level 3 available-for-sale marketable securities for the three months ended March 31, 2017. There were no transfers of financial assets between Levels 1, 2, or 3 classifications during the three months ended March 31, 2017.

Restricted Cash

Restricted Cash	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Restricted Cash	6. Restricted Cash The Company is required to maintain stand-by letters of credit as security deposits under each of its leases, one for its operating facility in Shelton, Connecticut and the other for its office space in Stamford, Connecticut (refer to Note 14, Commitments and Contingencies The restricted cash balance for the Shelton lease remains at $700 through the end of the lease term in October 2017. For the Stamford lease, the letter of credit balance remains at $769 for the first three years following commencement of the Stamford lease and may, upon request from the Company, thereafter be reduced to $408 through the end of the lease term in 2023. The reduction in the balance of the letter of credit for the Stamford lease is contingent upon the Company not being in default of any provisions of that lease prior to request for the reduction. As of March 31, 2017 and December 31, 2016, the Company had $700 of restricted cash related to the Shelton lease in current assets and $769 of restricted cash related to the Stamford lease in long-term assets.

Prepaid Expenses

Prepaid Expenses	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Prepaid Expenses	7. Prepaid expenses As of March 31, 2017, prepaid expenses were $1,979, consisting of $1,109 of prepaid R&D clinical costs, $682 of prepaid insurance and $188 of other prepaid costs. As of December 31, 2016, prepaid expenses were $1,530 consisting of $1,256 of prepaid R&D clinical costs, $112 of prepaid insurance and $162 of other prepaid costs.

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	3 Months Ended
	Mar. 31, 2017
Payables and Accruals [Abstract]
Accounts Payable and Accrued Expenses	8. Accounts Payable and Accrued Expenses Accounts payable and accrued expenses consist of the following: March 31, 2017 December 31, 2016 Accounts payable $ 1,688 $ 4,738 Accrued research projects 8,861 4,352 Accrued professional fees 688 163 Accrued compensation and benefits 681 1,514 Accrued other 594 766 Total $ 12,512 $ 11,533

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity On March 30, 2017, the Company entered into an underwriting agreement with Piper Jaffray & Co. and Stifel, Nicolaus & Company, Incorporated, as representatives of the several underwriters named therein, relating to the issuance and sale by the Company of up to 5,117,500 shares of its common stock, including 667,500 shares of common stock the underwriters had the option to purchase, at a public offering price of $18.00 per share (the “Offering”). The Offering was made pursuant to the Company’s Registration Statement on Form S-3 (File No. 333-216657), filed with the SEC on March 13, 2017 and declared effective on March 24, 2017, and a related prospectus supplement dated March 30, 2017, which was filed with the SEC on March 31, 2017. On April 5, 2017, the Company closed the Offering, including the full exercise of the underwriters’ option to purchase 667,500 additional shares of common stock. The Company received net proceeds of approximately $86,518, after deducting the underwriting discounts and commissions but before deducting offering expenses payable by the Company, which the Company currently estimates to be approximately $530.

Collaborations

Collaborations	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborations	10. Collaborations Maruishi Pharmaceutical Co., Ltd. In April 2013, the Company entered into a license agreement with Maruishi (the “Maruishi Agreement”) under which the Company granted Maruishi an exclusive license to develop, manufacture, and commercialize drug products containing CR845 for acute pain and uremic pruritus in Japan. Maruishi has the right to grant sub-licenses in Japan, which entitle the Company to receive sub-license fees, net of prior payments made by Maruishi to the Company. Under the Maruishi Agreement, the Company and Maruishi are required to use commercially reasonable efforts, at their own expense, to develop, obtain regulatory approval for and commercialize CR845 in the United States and Japan, respectively. In addition, the Company provided Maruishi specific clinical development services for CR845 used in Maruishi’s field of use. At inception of the Maruishi Agreement, the Company identified two deliverables under ASC 605-25, Revenue Recognition — Multiple Element Arrangements In March 2017, Maruishi entered into a sub-license agreement with Kissei Pharmaceutical Co. Ltd. for the development and sales/marketing of CR845 (called MR13A9 by Maruishi) for the treatment of uremic pruritus in dialysis patients in Japan. Consequently, for the three months ended March 31, 2017, the Company recognized revenue of $843 related to the sub-license fee. The Company allocated the amount of the sub-license fee to each of the two identified deliverables in the same proportion as the upfront license fee that the Company received at inception of the Maruishi Agreement. Accordingly, $530 was recognized as license and milestone fees revenue and $313 was recognized as collaborative revenue. As of March 31, 2017, the Company was due the full amount of the sub-license fee, which was recorded in Other receivables on the Balance Sheet. Such amount was received in April 2017. During the three months ended March 31, 2017 and 2016, the Company recognized clinical compound revenue of $68 and $7, respectively, from the sale of clinical compound to Maruishi. The Company incurred R&D expense related to the Maruishi Agreement of $61, consisting of cost of clinical compound, during the three months ended March 31, 2017.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Net Loss Per Share	11. Net Loss Per Share The Company computes basic net income (loss) per share by dividing net income (loss) by the weighted-average number of shares of common stock outstanding. Diluted net income per share includes the potential dilutive effect of common stock equivalents as if such securities were exercised during the period, when the effect is dilutive. Common stock equivalents may include outstanding stock options, which are included using the treasury stock method when dilutive. For the three months ended March 31, 2017 and 2016, the Company excluded the effects of potentially dilutive shares that were outstanding during those respective periods from the denominator as their inclusion would be anti-dilutive due to the Company’s net losses during those periods. The denominators used in the net loss per share computations are as follows: Three Months Ended March 31, 2017 2016 Basic: Weighted average common shares outstanding 27,299,678 27,259,589 Diluted: Weighted average common shares outstanding -Basic 27,299,678 27,259,589 Common stock options* — — Denominator for diluted net loss per share 27,299,678 27,259,589 * No amounts were considered as their effects would be anti-dilutive. Basic and diluted net loss per share are computed as follows: Three Months Ended March 31, 2017 2016 Net loss $ (22,204 ) $ (10,692 ) Weighted-average common shares outstanding: Basic and Diluted 27,299,678 27,259,589 Net loss per share, Basic and Diluted $ (0.81 ) $ (0.39 ) As of March 31, 2017 and 2016, 3,154,617 and 2,214,492 stock options, respectively, were outstanding, which could potentially dilute basic earnings per share in the future, but were not included in the computation of diluted net loss per share because to do so would have been anti-dilutive. In addition, on April 5, 2017, the Company issued 5,117,500 shares of its common stock pursuant to the Offering (see Note 9, Stockholders’ Equity

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	12. Stock-Based Compensation 2014 Equity Incentive Plan The Company’s 2014 Equity Incentive Plan, or the 2014 Plan, is administered by the Company’s Board of Directors or a duly authorized committee thereof, referred to as the Plan administrator. The 2014 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards, stock appreciation rights, performance stock awards and other forms of equity compensation, collectively referred to as Stock Awards. Additionally, the 2014 Plan provides for the grant of performance cash awards. Incentive stock options may be granted only to employees. All other awards may be granted to employees, including officers, non-employee directors, and consultants. No incentive stock options may be granted under the 2014 Plan after the tenth anniversary of the effective date of the 2014 Plan. Stock Awards granted under the 2014 Plan vest at the rate specified by the Plan administrator, which, for employees and non-employee consultants, has generally been 25% on the first anniversary of the date of grant and the balance ratably over the next 36 months. As of January 1, 2016, subsequent grants of Stock Awards made to employees and non-employee consultants vest monthly over a period of four years from the grant date. Stock options initially granted to members of the Company’s Board of Directors vest on the date of the Annual Meeting of Stockholders at which their initial term expires based on the class of Director. Subsequent grants to Directors that are made automatically at Annual Meetings of Stockholders vest fully on the first anniversary of the date of grant. The Plan administrator determines the term of Stock Awards granted under the 2014 Plan up to a maximum of ten years. The aggregate number of shares of the Company’s common stock reserved for issuance under the 2014 Plan will automatically increase on January 1 of each year, beginning on January 1, 2015 and continuing through and including January 1, 2024, by 3% of the total number of shares of the Company’s capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by the Company’s Board of Directors. On January 1, 2017, the aggregate number of shares of common stock that may be issued pursuant to stock awards under the 2014 Plan automatically increased from 3,101,707 to 3,920,613. The maximum number of shares that may be issued pursuant to the exercise of incentive stock options under the 2014 Plan is 30,000,000 shares. Under the 2014 Plan, the Company granted 748,500 and 610,000 stock options during the three months ended March 31, 2017 and 2016, respectively. The fair values of stock options granted during the three months ended March 31, 2017 and 2016 were estimated as of the dates of grant using the Black-Scholes option pricing model with the following assumptions: Three Months Ended March 31, 2017 2016 Risk-free interest rate 2.07% - 2.57% 1.40% -1.59% Expected volatility 75.3% - 80.7% 67.8% - 69.7% Expected dividend yield 0% 0% Expected life of employee options (in years) 6.25 6.25 Expected life of nonemployee options (in years) 10 10 The weighted-average grant date fair value of options granted to employees during the three months ended March 31, 2017 and 2016 was $12.27 and $3.85, respectively. As of March 31, 2017 and 2016, the Company used the Black-Scholes option valuation model with the following ranges of assumptions to re-measure the fair value of all outstanding options that had been granted to non-employee consultants during the vesting period of each tranche in accordance with ASC 505-50: March 31, 2017 2016 Risk-free interest rate 2.10% -2.39% 1.53% Expected volatility 74.6% - 78.4% 72.30% Expected dividend yield 0% 0% Expected life of non-employee options (in years) 6.83 - 9.94 7.84 The weighted-average fair value of outstanding options that had been granted to nonemployee consultants, as re-measured during the vesting period of each tranche in accordance with ASC 505-50, was $12.14 and $3.82 as of March 31, 2017 and 2016, respectively. On January 1, 2017, the Company adopted ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting Basis of Presentation Recently Adopted Accounting Pronouncements During the three months ended March 31, 2017 and 2016, the Company recognized compensation expense relating to stock options, as follows: Three Months Ended March 31, 2017 2016 Research and development $ 563 $ 189 General and administrative 545 307 Total stock option expense $ 1,108 $ 496 A summary of stock option award activity related to employees, non-employee members of the Company’s Board of Directors and non-employee consultants as of and for the three months ended March 31, 2017 is presented below: Number of Weighted Outstanding, December 31, 2016 2,548,408 $ 8.75 Granted 748,500 17.40 Exercised (27,291 ) 5.47 Forfeited (115,000 ) 7.74 Outstanding, March 31, 2017 3,154,617 $ 10.87 Options exercisable, March 31, 2017 1,097,711 The Company does not expect to realize any tax benefits from its stock option activity or the recognition of stock-based compensation expense because the Company currently has net operating losses and has a full valuation allowance against its deferred tax assets. Accordingly, no amounts related to excess tax benefits have been reported in cash flows from operations for the three months ended March 31, 2017 and 2016.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes For the three months ended March 31, 2017 and 2016, pre-tax losses were $22,235 and $10,837, respectively. The Company recognized a full tax valuation allowance against its deferred tax assets as of March 31, 2017 and December 31, 2016. Upon adoption of ASU 2016-09 on January 1, 2017, the tax benefit related to the exercise of stock options is recognized as a deferred tax asset that is offset by a corresponding valuation allowance. The benefit from income taxes of $31 and $145 for the three months ended March 31, 2017 and 2016, respectively, relates to state R&D tax credits exchanged for cash pursuant to the Connecticut R&D Tax Credit Exchange Program, which permits qualified small businesses engaged in R&D activities within Connecticut to exchange their unused R&D tax credits for a cash amount equal to 65% of the value of the exchanged credits.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. Commitments and Contingencies Contractual obligations and commitments as of March 31, 2017, consisting of future minimum lease payments under the Company’s Stamford and Shelton leases, were as follows: Payment Due for the Year Ending December 31, 2017 2018 2019 2020 2021 Thereafter Total Stamford operating lease $ 587 $ 1,093 $ 1,217 $ 1,241 $ 1,266 $ 2,383 $ 7,787 Shelton operating lease 506 — — — — — 506 $ 1,093 $ 1,093 $ 1,217 $ 1,241 $ 1,266 $ 2,383 $ 8,293 Stamford Operating Lease In December 2015, the Company entered into a lease agreement, or the Stamford Lease, with Four Stamford Plaza Owner LLC, or the Landlord, for office space in Stamford, Connecticut, or the Premises, for the purpose of relocating its headquarters. The initial term of the Stamford Lease commenced in May 2016, or the Commencement Date, and ends in November 2023. The Stamford Lease requires monthly lease payments, including rent escalations and rent holidays, during the initial lease term. The Company began to make rental payments from the Commencement Date. The Company records monthly rent expense on a straight-line basis from March 2016, upon taking possession of the Premises, through October 2023. As of March 31, 2017 and December 31, 2016, the balance of deferred lease obligation, representing the difference between cash rent paid and straight-line rent expense, was $567 and $583, respectively. The Stamford Lease is renewable for one five-year term. As of the Commencement Date, the Stamford landlord had made tenant improvements of approximately $1,094 to the leased premises. Such amount was included in Property and equipment, net and in Deferred lease obligation on the Company’s Balance Sheet on that date. The portion of Deferred lease obligation that is related to tenant improvements is being amortized as a reduction to rent expense over the same term as rent expense. As of March 31, 2017 and December 31, 2016, the balance of Deferred lease obligation related to tenant improvements was $951 and $987, respectively. In connection with the signing of the Stamford Lease, the Company entered into a standby letter of credit agreement for $769, which serves as a security deposit for the Premises. The standby letter of credit is automatically renewed annually through November 2023. This standby letter of credit is secured with restricted cash in a money market account (refer to Note 6, Restricted Cash Shelton Operating Lease In May 2016, the Company relocated its headquarters to Stamford, Connecticut and vacated its former operating facility in Shelton, Connecticut, although the Company continues to lease its former Shelton operating facility under an operating lease, or the Shelton Lease, which commenced in 2007 and terminates on October 13, 2017. The Shelton Lease, requires monthly lease payments through its term. The Company recorded monthly rent expense associated with the Shelton Lease on a straight-line basis from inception of the Shelton Lease through May 2016. In accordance with the accounting guidance in ASC 420-10-25-13 regarding exit or disposal cost obligations, as of May 2016, the Company recorded rent expense, within R&D expense and General and administrative expense, and accrued a liability of $1,312, which represents the fair value of costs that will continue to be incurred during the remaining term of the Shelton Lease without economic benefit to the Company. As of March 31, 2017, the carrying amount of the liability of $515, which includes the $506 of minimum rental payments in the table above, together with common area maintenance charges, was included in Accounts payable and accrued expenses on the Company’s Balance Sheet. A reconciliation of the balances of the accrued Shelton Lease cease-use liability for the three months ended March 31, 2017 is as follows: Balance, December 31, 2016 $ 756 Rental payments (247 ) Interest accretion 6 Balance, March 31, 2017 $ 515 In conjunction with the signing of the Shelton Lease, the Company entered into a standby letter of credit agreement, which expires on May 31, 2017, as a security deposit for the premises. As of March 31, 2017 and December 31, 2016, the balance of the letter of credit was $700, which is secured with restricted cash (refer to Note 6, Restricted Cash The Company accelerated the amortization of the Shelton leasehold improvements from the date of signing of the Stamford Lease in December 2015 through the date that the Company vacated the Shelton facility in May 2016. Additional amortization expense as a result of such acceleration amounted to $539 (additional net loss per share of $0.02) for the three months ended March 31, 2016.

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from the Company’s estimates and assumptions. Significant estimates include the fair value of marketable securities that are classified as level 2 of the fair value hierarchy, useful lives of fixed assets, the periods over which certain revenues will be recognized, including licensing and collaborative revenue recognized from non-refundable up-front and milestone payments, the determination of prepaid research and development, or R&D, clinical costs and accrued research projects, the amount of non-cash compensation costs related to share-based payments to employees and non-employees and the periods over which those costs are expensed and the likelihood of realization of deferred tax assets.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes to the significant accounting policies previously disclosed in Note 2 to the Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.
Recent Accounting Pronouncements	Accounting Pronouncements Recently Adopted As of January 1, 2017, the Company adopted Accounting Standards Update, or ASU, No. 2016-09, Improvements to Employee Share-Based Payment Accounting Topic 718 Compensation – Stock Compensation Recent Accounting Pronouncements Not Yet Adopted In January 2017, the Financial Accounting Standards Board issued ASU No. 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business, ,

Available-for-Sale Marketable24

Available-for-Sale Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Marketable Securities by Major Type of Security	The following tables summarize the Company’s available-for-sale marketable securities by major type of security as of March 31, 2017 and December 31, 2016: As of March 31, 2017 Gross Unrealized Estimated Fair Value Type of Security Amortized Cost Gains Losses Money market funds $ 7,231 $ 28 $ — $ 7,259 U.S. Treasury securities 2,512 — (2 ) 2,510 U.S. government agency obligations 1,500 — — 1,500 Corporate bonds 11,005 1 (3 ) 11,003 Commercial paper 9,232 — — 9,232 Total available-for-sale marketable securities $ 31,480 $ 29 $ (5 ) $ 31,504 As of December 31, 2016 Gross Unrealized Estimated Type of Security Amortized Cost Gains Losses Money market funds $ 8,268 $ 8 $ — $ 8,276 U.S. Treasury securities 2,523 — (1 ) 2,522 U.S. government agency obligations 3,501 1 — 3,502 Corporate bonds 16,683 — (6 ) 16,677 Commercial paper 15,206 3 (2 ) 15,207 Total available-for-sale marketable securities $ 46,181 $ 12 $ (9 ) $ 46,184
Schedule of Fair Values and Amortized Cost of Marketable Debt Securities by Contractual Maturity	The Company classifies its marketable debt securities based on their contractual maturity dates. As of March 31, 2017, the Company’s marketable debt securities mature at various dates through August 2017. The fair values and amortized cost of marketable debt securities by contractual maturity were as follows. The table does not include money market funds that are classified as available-for-sale marketable securities. As of March 31, 2017 As of December 31, 2016 Contractual maturity Amortized Cost Fair Value Amortized Cost Fair Value Less than one year $ 24,249 $ 24,245 $ 37,913 $ 37,908
Schedule of Fair Values and Continuous Unrealized Loss Positions of Available-for-Sale Marketable Securities	The following tables show the fair value of the Company’s available-for-sale marketable securities that have unrealized losses and that are deemed to be only temporarily impaired, aggregated by investment category and length of time that the individual investments have been in a continuous unrealized loss position. As of March 31, 2017 Less than 12 Months 12 Months or Greater Total Fair Value Gross Fair Value Gross Fair Value Gross U.S. Treasury securities $ 2,510 $ (2 ) $ — $ — $ 2,510 $ (2 ) Corporate bonds 7,751 (3 ) — — 7,751 (3 ) Total $ 10,261 $ (5 ) $ — $ — $ 10,261 $ (5 ) As of December 31, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Gross Fair Value Gross Fair Value Gross U.S. Treasury securities $ 2,522 $ (1 ) $ — $ — $ 2,522 $ (1 ) Corporate bonds 9,919 (6 ) — — 9,919 (6 ) Commercial paper 5,227 (2 ) — — 5,227 (2 ) Total $ 17,668 $ (9 ) $ — $ — $ 17,668 $ (9 )

Accumulated Other Comprehensi25

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Summary of Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax, from Unrealized Gains (Losses) on Available-for-Sale Marketable Securities	The following table summarizes the changes in accumulated other comprehensive income (loss), or AOCI, net of tax, from unrealized gains (losses) on available-for-sale marketable securities, the Company’s only component of AOCI, for the three months ended March 31, 2017 and March 31, 2016. Total Accumulated Balance, December 31, 2016 $ 3 Other comprehensive income before reclassifications 24 Amount reclassified from accumulated other comprehensive income (3 ) Net current period other comprehensive income 21 Balance, March 31, 2017 $ 24 Balance, December 31, 2015 $ (35 ) Other comprehensive income before reclassifications 39 Amount reclassified from accumulated other comprehensive income — Net current period other comprehensive income 39 Balance, March 31, 2016 $ 4
Schedule of Reclassification Out of Accumulated Other Comprehensive Income	The reclassifications out of AOCI and into net loss were as follows: Three Months Affected Line Item in Component of AOCI 2017 2016 Unrealized gains (losses) on available-for-sale marketable securities $ 3 $ — Other income — — Income tax benefit $ 3 $ — Net of tax

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Summary of Financial Assets Measured at Fair Value on Recurring Basis	The following tables summarize the Company’s financial assets measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016. Fair value measurement as of March 31, 2017: Financial assets Quoted prices in Significant other Significant active markets for observable unobservable identical assets inputs inputs Type of Instrument Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents: Money market fund and checking accounts $ 5,306 $ 5,306 $ — $ — Available-for-sale marketable securities: Money market funds 7,259 — 7,259 — U.S. Treasury securities 2,510 — 2,510 — U.S. government agency obligations 1,500 — 1,500 — Corporate bonds 11,003 — 11,003 — Commercial paper 9,232 — 9,232 — Restricted cash: Commercial money market account 1,469 1,469 — — Total financial assets $ 38,279 $ 6,775 $ 31,504 $ — Fair value measurement as of December 31, 2016: Financial assets Quoted prices in Significant other Significant active markets for observable unobservable identical assets inputs inputs Type of Instrument Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents: Money market fund and checking accounts $ 12,092 $ 12,092 $ — $ — Available-for-sale marketable securities: Money market fund 8,276 — 8,276 — U.S. Treasury securities 2,522 — 2,522 — U.S. government agency obligations 3,502 — 3,502 — Corporate bonds 16,677 — 16,677 — Commercial paper 15,207 — 15,207 — Restricted cash: Money market fund 1,469 1,469 — — Total financial assets $ 59,745 $ 13,561 $ 46,184 $ —

Accounts Payable and Accrued 27

Accounts Payable and Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2017
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consist of the following: March 31, 2017 December 31, 2016 Accounts payable $ 1,688 $ 4,738 Accrued research projects 8,861 4,352 Accrued professional fees 688 163 Accrued compensation and benefits 681 1,514 Accrued other 594 766 Total $ 12,512 $ 11,533

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Computation of Denominators Used in Net Loss per Share	The denominators used in the net loss per share computations are as follows: Three Months Ended March 31, 2017 2016 Basic: Weighted average common shares outstanding 27,299,678 27,259,589 Diluted: Weighted average common shares outstanding -Basic 27,299,678 27,259,589 Common stock options* — — Denominator for diluted net loss per share 27,299,678 27,259,589 * No amounts were considered as their effects would be anti-dilutive.
Computation of Basic and Diluted Net Loss per Share	Basic and diluted net loss per share are computed as follows: Three Months Ended March 31, 2017 2016 Net loss $ (22,204 ) $ (10,692 ) Weighted-average common shares outstanding: Basic and Diluted 27,299,678 27,259,589 Net loss per share, Basic and Diluted $ (0.81 ) $ (0.39 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2017
Summary of Assumptions Used in Black-Scholes Option Pricing Model	The fair values of stock options granted during the three months ended March 31, 2017 and 2016 were estimated as of the dates of grant using the Black-Scholes option pricing model with the following assumptions: Three Months Ended March 31, 2017 2016 Risk-free interest rate 2.07% - 2.57% 1.40% -1.59% Expected volatility 75.3% - 80.7% 67.8% - 69.7% Expected dividend yield 0% 0% Expected life of employee options (in years) 6.25 6.25 Expected life of nonemployee options (in years) 10 10
Summary of Compensation Expense Relating to Stock Options	During the three months ended March 31, 2017 and 2016, the Company recognized compensation expense relating to stock options, as follows: Three Months Ended March 31, 2017 2016 Research and development $ 563 $ 189 General and administrative 545 307 Total stock option expense $ 1,108 $ 496
Summary of Stock Option Activity	A summary of stock option award activity related to employees, non-employee members of the Company’s Board of Directors and non-employee consultants as of and for the three months ended March 31, 2017 is presented below: Number of Weighted Outstanding, December 31, 2016 2,548,408 $ 8.75 Granted 748,500 17.40 Exercised (27,291 ) 5.47 Forfeited (115,000 ) 7.74 Outstanding, March 31, 2017 3,154,617 $ 10.87 Options exercisable, March 31, 2017 1,097,711
Re-Measurement [Member]
Summary of Assumptions Used in Black-Scholes Option Pricing Model	As of March 31, 2017 and 2016, the Company used the Black-Scholes option valuation model with the following ranges of assumptions to re-measure the fair value of all outstanding options that had been granted to non-employee consultants during the vesting period of each tranche in accordance with ASC 505-50: March 31, 2017 2016 Risk-free interest rate 2.10% -2.39% 1.53% Expected volatility 74.6% - 78.4% 72.30% Expected dividend yield 0% 0% Expected life of non-employee options (in years) 6.83 - 9.94 7.84

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Contractual Obligations and Commitments Consisting of Future Minimum Lease Payments	Contractual obligations and commitments as of March 31, 2017, consisting of future minimum lease payments under the Company’s Stamford and Shelton leases, were as follows: Payment Due for the Year Ending December 31, 2017 2018 2019 2020 2021 Thereafter Total Stamford operating lease $ 587 $ 1,093 $ 1,217 $ 1,241 $ 1,266 $ 2,383 $ 7,787 Shelton operating lease 506 — — — — — 506 $ 1,093 $ 1,093 $ 1,217 $ 1,241 $ 1,266 $ 2,383 $ 8,293
Schedule of Reconciliation of Balances of Accrued Shelton Lease Cease-Use Liability	A reconciliation of the balances of the accrued Shelton Lease cease-use liability for the three months ended March 31, 2017 is as follows: Balance, December 31, 2016 $ 756 Rental payments (247 ) Interest accretion 6 Balance, March 31, 2017 $ 515

Business - Additional Informati

Business - Additional Information (Detail) - USD ($) $ in Thousands	Apr. 05, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Nature Of Business [Line Items]
Date of formation		Jul. 2, 2004
Proceeds from equity and debt financing		$ 204,800
Upfront and milestone payments received in connection with license agreements		33,500
Unrestricted cash and cash equivalents and marketable securities		36,810
Accumulated deficit		(184,420)		$ (162,171)
Net loss		(22,204)	$ (10,692)
Net cash used in operating activities		$ (21,636)	$ (9,833)
Follow-on Public Offering [Member] | Subsequent Event [Member] | Common Stock [Member]
Nature Of Business [Line Items]
Net proceeds from offering of common stock	$ 86,518

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail) $ in Thousands	Jan. 01, 2017USD ($)
ASU 2016-09 [Member]
Basis Of Presentation [Line Items]
Cumulative-effect adjustment in equity	$ 45

Available-for-Sale Marketable33

Available-for-Sale Marketable Securities - Summary of Available-for-Sale Marketable Securities by Major Type of Security (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 31,480	$ 46,181
Gross Unrealized Gains	29	12
Gross Unrealized Losses	(5)	(9)
Estimated Fair Value	31,504	46,184
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,231	8,268
Gross Unrealized Gains	28	8
Estimated Fair Value	7,259	8,276
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,512	2,523
Gross Unrealized Losses	(2)	(1)
Estimated Fair Value	2,510	2,522
US Government Corporations and Agencies Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,500	3,501
Gross Unrealized Gains		1
Estimated Fair Value	1,500	3,502
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,005	16,683
Gross Unrealized Gains	1
Gross Unrealized Losses	(3)	(6)
Estimated Fair Value	11,003	16,677
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,232	15,206
Gross Unrealized Gains		3
Gross Unrealized Losses		(2)
Estimated Fair Value	$ 9,232	$ 15,207

Available-for-Sale Marketable34

Available-for-Sale Marketable Securities - Schedule of Fair Values and Amortized Cost of Marketable Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Fair value of marketable debt securities, contractual maturity, Less than one year	$ 24,245	$ 37,908
Amortized Cost of marketable debt securities, contractual maturity, Less than one year	$ 24,249	$ 37,913

Available-for-Sale Marketable35

Available-for-Sale Marketable Securities - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Position	Dec. 31, 2016Position
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sale of available-for-sale marketable securities	$ 5,030
Realized gains	$ 3
Number of available-for-sale marketable securities in unrealized loss positions | Position	16	18
Total number of positions | Position	24	34
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sale of available-for-sale marketable securities	$ 5,030
Realized gains	$ 3

Available-for-Sale Marketable36

Available-for-Sale Marketable Securities - Schedule of Fair Values and Continuous Unrealized Loss Positions of Available-for-Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Fair Value	$ 10,261	$ 17,668
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Gross Unrealized Losses	(5)	(9)
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Fair Value	0	0
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-sale marketable securities, continuous unrealized loss position, Fair Value	10,261	17,668
Available-for-sale marketable securities, continuous unrealized loss position, Gross Unrealized Losses	(5)	(9)
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Fair Value	2,510	2,522
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Gross Unrealized Losses	(2)	(1)
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Fair Value	0	0
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-sale marketable securities, continuous unrealized loss position, Fair Value	2,510	2,522
Available-for-sale marketable securities, continuous unrealized loss position, Gross Unrealized Losses	(2)	(1)
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Fair Value	7,751	9,919
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Gross Unrealized Losses	(3)	(6)
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Fair Value	0	0
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-sale marketable securities, continuous unrealized loss position, Fair Value	7,751	9,919
Available-for-sale marketable securities, continuous unrealized loss position, Gross Unrealized Losses	$ (3)	(6)
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Fair Value		5,227
Available-for-sale marketable securities, continuous unrealized loss position, Less than 12 Months, Gross Unrealized Losses		(2)
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Fair Value		0
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Gross Unrealized Losses		0
Available-for-sale marketable securities, continuous unrealized loss position, Fair Value		5,227
Available-for-sale marketable securities, continuous unrealized loss position, Gross Unrealized Losses		$ (2)

Accumulated Other Comprehensi37

Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax, from Unrealized Gains (Losses) on Available-for-Sale Marketable Securities (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ 3	$ (35)
Other comprehensive income before reclassifications	24	39
Amount reclassified from accumulated other comprehensive income	(3)
Net current period other comprehensive income	21	39
Total Accumulated Other Comprehensive Income (Loss), Ending Balance	$ 24	$ 4

Accumulated Other Comprehensi38

Accumulated Other Comprehensive Income (Loss) - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized gains on sale of securities,Other income	$ 90	$ 149
Income tax benefit	(31)	(145)
Net of tax	3
Accumulated Net Unrealized Investment Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized gains on sale of securities,Other income	3
Income tax benefit	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financial assets
Restricted cash	$ 769	$ 769
Recurring [Member]
Financial assets
Total financial assets	38,279	59,745
Recurring [Member] | US Government Corporations and Agencies Securities [Member]
Financial assets
Available-for-sale marketable securities	1,500	3,502
Recurring [Member] | Corporate Bonds [Member]
Financial assets
Available-for-sale marketable securities	11,003	16,677
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets
Total financial assets	6,775	13,561
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets
Total financial assets	31,504	46,184
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | US Government Corporations and Agencies Securities [Member]
Financial assets
Available-for-sale marketable securities	1,500	3,502
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds [Member]
Financial assets
Available-for-sale marketable securities	11,003	16,677
Recurring [Member] | Money Market Funds [Member]
Financial assets
Cash and cash equivalents	5,306	12,092
Available-for-sale marketable securities	7,259	8,276
Restricted cash		1,469
Recurring [Member] | Money Market Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets
Cash and cash equivalents	5,306	12,092
Restricted cash		1,469
Recurring [Member] | Money Market Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets
Available-for-sale marketable securities	7,259	8,276
Recurring [Member] | U.S. Treasury Securities [Member]
Financial assets
Available-for-sale marketable securities	2,510	2,522
Recurring [Member] | U.S. Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets
Available-for-sale marketable securities	2,510	2,522
Recurring [Member] | Commercial Paper [Member]
Financial assets
Available-for-sale marketable securities	9,232	15,207
Recurring [Member] | Commercial Paper [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets
Available-for-sale marketable securities	9,232	$ 15,207
Recurring [Member] | Commercial Money Market Account [Member]
Financial assets
Restricted cash	1,469
Recurring [Member] | Commercial Money Market Account [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets
Restricted cash	$ 1,469

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases of financial assets	$ 0
Sales of financial assets	0
Maturities of financial assets	0
Transfer of financial asset into level 3 of fair value	0
Fair value assets level 2 to level 1 transfers	0
Fair value assets level 1 to level 2 transfers	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unrealized gains	0
Unrealized losses	$ 0

Restricted Cash - Additional In

Restricted Cash - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash in current assets	$ 700	$ 700
Restricted cash balance	769	769
Shelton Lease [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash in current assets	$ 700	700
Lease term	2017-10
Stamford Lease [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Lease term	2023-10
Letter of credit, remaining amount	$ 769
Letter of credit, remaining amount after three years	408
Restricted cash balance	$ 769	$ 769

Prepaid Expenses - Additional I

Prepaid Expenses - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 1,979	$ 1,530
Prepaid R&D clinical costs	1,109	1,256
Prepaid insurance	682	112
Other prepaid costs	$ 188	$ 162

Accounts Payable and Accrued 43

Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts payable	$ 1,688	$ 4,738
Accrued research projects	8,861	4,352
Accrued professional fees	688	163
Accrued compensation and benefits	681	1,514
Accrued other	594	766
Total	$ 12,512	$ 11,533

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Apr. 05, 2017	Mar. 31, 2017	Mar. 30, 2017
Subsidiary, Sale of Stock [Line Items]
Common stock, shares subscribed		5,117,500
Common Stock [Member] | Follow-on Public Offering [Member]
Subsidiary, Sale of Stock [Line Items]
Public offering price per share		$ 18	$ 18
Common Stock [Member] | Follow-on Public Offering [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Net proceeds from offering of common stock	$ 86,518
Common stock, shares issued	5,117,500
Common Stock [Member] | Follow-on Public Offering [Member] | Subsequent Event [Member] | Scenario, Forecast [Member]
Subsidiary, Sale of Stock [Line Items]
Estimated offering expenses payable	$ 530
Maximum [Member] | Common Stock [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock, shares subscribed			5,117,500
Maximum [Member] | Common Stock [Member] | Underwriter's Over-Allotment [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock, shares subscribed			667,500
Maximum [Member] | Common Stock [Member] | Underwriter's Over-Allotment [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock, shares issued	667,500

Collaborations - Additional Inf

Collaborations - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Deliverables	Mar. 31, 2016USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and milestone fee revenue	$ 530
Collaborative revenue	313
Clinical compound revenue	68	$ 7
Maruishi Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and milestone fee revenue	$ 530
Number of deliverables for revenue recognized | Deliverables	2
Collaborative revenue	$ 313
Sub-license fee	843
Clinical compound revenue	68	$ 7
Cost of clinical compound	$ 61

Net Loss per Share - Computatio

Net Loss per Share - Computation of Denominators Used in Net Loss per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Basic:
Weighted average common shares outstanding	27,299,678	27,259,589
Diluted:
Weighted average common shares outstanding -Basic	27,299,678	27,259,589
Common stock options	0	0
Denominator for diluted net loss per share	27,299,678	27,259,589

Net Loss per Share - Computat47

Net Loss per Share - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Net loss	$ (22,204)	$ (10,692)
Weighted-average common shares outstanding:
Basic and Diluted	27,299,678	27,259,589
Net loss per share, Basic and Diluted	$ (0.81)	$ (0.39)

Net Loss per Share - Additional

Net Loss per Share - Additional Information (Detail) - shares	Apr. 05, 2017	Mar. 31, 2017	Mar. 31, 2016
Subsequent Event [Member] | Common Stock [Member] | Follow-on Public Offering [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock issued	5,117,500
Employee Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents		3,154,617	2,214,492

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jan. 01, 2016	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2015	Jan. 01, 2017
ASU 2016-09 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative-effect adjustment in equity					$ 45
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of options granted		$ 12.27	$ 3.85
Nonemployee Consultants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair values of outstanding options		$ 12.14	$ 3.82
2014 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options that may be granted after the tenth anniversary of the 2014 Plan		0
Annual increases in number of shares reserved for issuance as a percentage of shares of capital stock outstanding through January 1, 2024				3.00%
Share-based compensation arrangement by share-based payment award, number of shares authorized	3,101,707				3,920,613
Options granted		748,500	610,000
2014 Equity Incentive Plan [Member] | Share-Based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vested shares on first anniversary of grant date		25.00%
2014 Equity Incentive Plan [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards granted		36 months
2014 Equity Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of awards granted		10 years
2014 Equity Incentive Plan [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards granted	4 years
2014 Equity Incentive Plan [Member] | Incentive Stock Options [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized				30,000,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Assumptions Used in Black-Scholes Option Pricing Model (Detail)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	2.07%	1.40%
Risk-free interest rate, maximum	2.57%	1.59%
Expected volatility, minimum	75.30%	67.80%
Expected volatility, maximum	80.70%	69.70%
Expected dividend yield	0.00%	0.00%
Employee Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options (in years)	6 years 3 months	6 years 3 months
Nonemployee Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options (in years)	10 years	10 years

Stock-Based Compensation - Su51

Stock-Based Compensation - Summary of Re-measurement of Assumptions Used in Black-Scholes Option Pricing Model (Detail)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	2.07%	1.40%
Risk-free interest rate, maximum	2.57%	1.59%
Expected volatility, minimum	75.30%	67.80%
Expected volatility, maximum	80.70%	69.70%
Expected dividend yield	0.00%	0.00%
Nonemployee Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options (in years)	10 years	10 years
Re-Measurement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate		1.53%
Risk-free interest rate, minimum	2.10%
Risk-free interest rate, maximum	2.39%
Expected volatility		72.30%
Expected volatility, minimum	74.60%
Expected volatility, maximum	78.40%
Expected dividend yield	0.00%	0.00%
Re-Measurement [Member] | Nonemployee Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options (in years)		7 years 10 months 2 days
Re-Measurement [Member] | Minimum [Member] | Nonemployee Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options (in years)	6 years 9 months 29 days
Re-Measurement [Member] | Maximum [Member] | Nonemployee Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options (in years)	9 years 11 months 9 days

Stock-Based Compensation - Su52

Stock-Based Compensation - Summary of Compensation Expense Relating to Stock Options (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock option expense	$ 1,108	$ 496
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock option expense	563	189
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock option expense	$ 545	$ 307

Stock-Based Compensation - Su53

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - 2014 Equity Incentive Plan [Member] - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding at December 31, 2016	2,548,408
Number of Options, Granted	748,500	610,000
Number of Options, Exercised	(27,291)
Number of Options, Forfeited	(115,000)
Number of Options, Outstanding at March 31 2017	3,154,617
Number of Options, Options exercisable at March 31 2017	1,097,711
Weighted-Average Exercise Price, Outstanding at December 31, 2016	$ 8.75
Weighted-Average Exercise Price, Granted	17.40
Weighted-Average Exercise Price, Exercised	5.47
Weighted-Average Exercise Price, Forfeited	7.74
Weighted-Average Exercise Price, Outstanding at March 31 2017	$ 10.87

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Pre-tax losses	$ (22,235)	$ (10,837)
Benefit from income taxes	$ (31)	$ (145)
Percentage of annual research and development credit for cash	65.00%

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Contractual Obligations and Commitments Consisting of Future Minimum Lease Payments (Detail) $ in Thousands	Mar. 31, 2017USD ($)
Operating Leased Assets [Line Items]
2,017	$ 1,093
2,018	1,093
2,019	1,217
2,020	1,241
2,021	1,266
Thereafter	2,383
Total	8,293
Stamford Operating Lease [Member]
Operating Leased Assets [Line Items]
2,017	587
2,018	1,093
2,019	1,217
2,020	1,241
2,021	1,266
Thereafter	2,383
Total	7,787
Shelton Operating Lease [Member]
Operating Leased Assets [Line Items]
2,017	506
Total	$ 506

Commitments and Contingencies56

Commitments and Contingencies - Additional Information (Detail) - USD ($)	May 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Other Commitments [Line Items]
Deferred lease obligation		$ 1,518,000		$ 1,570,000
Lease minimum rental payment		$ 8,293,000
Stamford Operating Lease [Member]
Other Commitments [Line Items]
Operating Lease, description		The Stamford Lease requires monthly lease payments, including rent escalations and rent holidays, during the initial lease term. The Company began to make rental payments from the Commencement Date. The Company records monthly rent expense on a straight-line basis from March 2016, upon taking possession of the Premises, through October 2023. As of March 31, 2017 and December 31, 2016, the balance of deferred lease obligation, representing the difference between cash rent paid and straight-line rent expense, was $567 and $583, respectively. The Stamford Lease is renewable for one five-year term.
Operating Lease, renewable term		5 years
Operating lease, expiration date		Oct. 31, 2023
Deferred lease obligation		$ 567,000		583,000
Tenant improvement expenses	$ 1,094,000
Lease minimum rental payment		7,787,000
Stamford Operating Lease [Member] | Leasehold Improvements [Member]
Other Commitments [Line Items]
Amortization of deferred lease obligation		951,000		987,000
Stamford Operating Lease [Member] | Standby Letter of Credit [Member]
Other Commitments [Line Items]
Letter of credit, amount		$ 769,000
Operating lease, renewable term description		Automatically renewed annually through November 2023.
Stamford Operating Lease [Member] | Maximum [Member] | Standby Letter of Credit [Member]
Other Commitments [Line Items]
Letter of credit, renewal date		Nov. 30, 2023
Shelton Operating Lease [Member]
Other Commitments [Line Items]
Operating lease, expiration date		Oct. 13, 2017
Accrued cease use date liability	$ 1,312,000
Lease minimum rental payment		$ 506,000
Restructuring liability		515,000		756,000
Additional amortization expense			$ 539,000
Additional loss per share			$ 0.02
Shelton Operating Lease [Member] | Standby Letter of Credit [Member]
Other Commitments [Line Items]
Letter of credit, remaining amount		$ 700,000		$ 700,000
Letter of credit, expiration date		May 31, 2017

Commitments and Contingencies57

Commitments and Contingencies - Schedule of Reconciliation of Balances of Accrued Shelton Lease Cease-Use Liability (Detail) - Shelton Operating Lease [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Restructuring Cost and Reserve [Line Items]
Balance, December 31, 2016	$ 756
Rental payments	(247)
Interest accretion	6
Balance, March 31, 2017	$ 515