Concert Pharmaceuticals (CNCE) 10-Q 9 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Nov. 06, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	CNCE
Entity Registrant Name	CONCERT PHARMACEUTICALS, INC.
Entity Central Index Key	1,367,920
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		22,772,604

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 32,119	$ 40,555
Investments, available for sale	174,993	55,630
Interest receivable	635	164
Accounts receivable	8	27
Prepaid expenses and other current assets	1,922	1,353
Total current assets	209,677	97,729
Property and equipment, net	2,111	2,199
Restricted cash	400	400
Other assets	41	67
Total assets	212,229	100,395
Current liabilities:
Accounts payable	481	545
Accrued expenses and other liabilities	3,402	3,853
Income taxes payable	2,177	0
Deferred revenue, current portion	1,388	1,172
Total current liabilities	7,448	5,570
Deferred revenue, net of current portion	8,921	8,878
Deferred lease incentive, net of current portion	0	249
Deferred rent, net of current portion	0	104
Total liabilities	16,369	14,801
Commitments
Stockholders’ equity:
Preferred stock, $0.001 par value per share; 5,000,000 shares authorized; no shares issued and outstanding in 2017 and 2016, respectively	0	0
Common stock, $0.001 par value per share; 100,000,000 shares authorized; 22,756,047 and 22,319,516 shares issued and 22,751,292 and 22,316,982 outstanding in 2017 and 2016, respectively	23	22
Additional paid-in capital	266,081	257,461
Accumulated other comprehensive loss	(67)	(7)
Accumulated deficit	(70,177)	(171,882)
Total stockholders’ equity	195,860	85,594
Total liabilities and stockholders’ equity	$ 212,229	$ 100,395

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
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
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)	22,756,047	22,319,516
Common stock, shares outstanding (in shares)	22,751,292	22,316,982

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
License and research and development revenue	$ 17	$ 26	$ 52	$ 153
Other revenue	143,827	0	143,827	0
Total revenue	143,844	26	143,879	153
Operating expenses:
Research and development	7,136	8,054	22,658	28,323
General and administrative	4,875	3,440	15,835	10,845
Total operating expenses	12,011	11,494	38,493	39,168
Income (loss) from operations	131,833	(11,468)	105,386	(39,015)
Investment income	450	112	742	338
Interest and other expense	(609)	0	(814)	0
Loss on extinguishment of debt	(1,432)	0	(1,432)	0
Income (loss) before tax provision	130,242	(11,356)	103,882	(38,677)
Provision for income taxes	2,177	0	2,177	0
Net income (loss)	128,065	(11,356)	101,705	(38,677)
Unrealized (loss) gain on investments	(23)	(10)	(60)	51
Comprehensive income (loss)	128,042	(11,366)	101,645	(38,626)
Net income (loss) attributable to common stockholders - basic	127,324	(11,356)	101,272	(38,677)
Net income (loss) attributable to common stockholders - diluted	$ 127,347	$ (11,356)	$ 101,284	$ (38,677)
Net income (loss) per share applicable to common stockholders
Basic (in dollars per share)	$ 5.61	$ (0.51)	$ 4.49	$ (1.74)
Diluted (in dollars per share)	$ 5.44	$ (0.51)	$ 4.37	$ (1.74)
Weighted-average number of common shares used in net income (loss) per share applicable to common stockholders:
Weighted average shares outstanding - basic (in shares)	22,694	22,229	22,551	22,215
Weighted average shares outstanding - diluted (in shares)	23,421	22,229	23,195	22,215

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net income (loss)	$ 101,705	$ (38,677)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	749	655
Stock-based compensation expense	5,713	3,831
Accretion of premiums and discounts on investments	106	401
Amortization of discount on loan payable	166	0
Amortization of deferred lease incentive	(242)	(235)
Loss on disposal of asset	4	2
Loss on extinguishment of debt	1,432	0
Changes in operating assets and liabilities:
Accounts receivable	19	57
Interest receivable	(471)	(142)
Prepaid expenses and other current assets	(569)	234
Other assets	26	59
Accounts payable	(64)	954
Accrued expenses and other liabilities	(507)	(778)
Income taxes payable	2,177	(75)
Deferred rent	(67)	(29)
Deferred revenue	259	(103)
Net cash provided by (used in) operating activities	110,436	(33,846)
Investing activities
Purchases of property and equipment	(653)	(295)
Purchases of investments	(180,986)	(126,785)
Maturities of investments	61,457	97,926
Net cash used in investing activities	(120,182)	(29,154)
Financing activities
Proceeds from loan, net	29,659	0
Repayment of loan	(30,745)	0
Proceeds from exercise of stock options	2,396	293
Net cash provided by financing activities	1,310	293
Net decrease in cash and cash equivalents	(8,436)	(62,707)
Cash and cash equivalents at beginning of period	40,555	92,510
Cash and cash equivalents at end of period	32,119	29,803
Supplemental cash flow information:
Cash paid for interest	648	0
Cash paid for income taxes	0	85
Purchases of property and equipment unpaid at period end	4	235
Issuance of stock warrants	$ 512	$ 0

Nature of Business

Nature of Business	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business Concert Pharmaceuticals, Inc., or Concert or the Company, was incorporated on April 12, 2006 as a Delaware corporation with operations based in Lexington, Massachusetts. The Company is a clinical stage biopharmaceutical company that applies its extensive knowledge of deuterium chemistry to discover and develop novel small molecule drugs. The Company’s approach typically starts with approved drugs that the Company believes can be improved with deuterium substitution to provide better pharmacokinetic or metabolic properties, thereby enhancing clinical safety, tolerability or efficacy. The Company believes this approach may enable drug discovery and clinical development that is more efficient and less expensive than conventional small molecule drug research and development. The Company has a pipeline of clinical candidates as well as research efforts to identify new product candidates. On March 3, 2017, the Company entered into an Asset Purchase Agreement (the "Asset Purchase Agreement") with Vertex Pharmaceuticals, Inc., through Vertex Pharmaceuticals (Europe) Limited ("Vertex"), pursuant to which the Company agreed to sell and assign CTP-656, now known as VX-561, and other cystic fibrosis assets of the Company, for up to $250 million subject to the satisfaction of certain closing conditions. On July 25, 2017, the Asset Purchase Agreement closed and Vertex paid the Company $160 million in cash consideration, with $16 million to initially be held in escrow. Additional information concerning the sale of CTP-656 is discussed further in Note 6. On June 8, 2017, the Company entered into a Loan and Security Agreement ("Loan Agreement") with Hercules Capital, Inc., ("Hercules"), pursuant to which Hercules agreed to make available to the Company a secured term loan facility in the amount of $30 million ("Term Loan Facility") subject to certain terms and conditions. On September 7, 2017, the Company paid off the outstanding obligation in full resulting in the termination of the Loan Agreement. Additional information concerning the prepayment of the Loan Agreement is discussed further in Note 11. The Company had cash and cash equivalents and investments of $207.1 million at September 30, 2017. The Company believes that its cash and cash equivalents and investments at September 30, 2017, will be sufficient to allow the Company to fund its current operating plan for at least the next twelve months. The Company may pursue additional cash resources through public or private financings and by establishing collaborations with or licensing its technology to other companies and through other arrangements. Since its inception, the Company has generated an accumulated deficit of $70.2 million through September 30, 2017. The Company's operating results may fluctuate significantly from year to year, depending on the timing and magnitude of cash payments received pursuant to collaboration and licensing arrangements and other agreements and the timing and magnitude of clinical trial and other development activities under its current development programs. Substantially all the Company's net losses have resulted from costs incurred in connection with its research and development programs and from general and administrative costs associated with its operations. With the exception of the revenue from the Asset Purchase Agreement with Vertex, the Company expects to continue to incur significant expenses and increasing operating losses for at least the next several years. The Company is subject to risks common to companies in the biotechnology industry, including, but not limited to, risks of failure or unsatisfactory results of nonclinical studies and clinical trials, the need to obtain additional financing to fund the future development of its pipeline, the need to obtain marketing approval for its product candidates, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development by competitors of technological innovations and ability to transition from pilot-scale manufacturing to large-scale production of products. Unless otherwise indicated, all amounts are in thousands except share and per share amounts.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments, consisting of normal recurring accruals and revisions of estimates, considered necessary for a fair presentation of the condensed consolidated financial statements have been included. Interim results for the three and nine months ended September 30, 2017 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2017 or any other future period. The accompanying condensed consolidated financial statements reflect the accounts of Concert and its subsidiaries. All intercompany transactions between the Company and its subsidiaries have been eliminated. Management has determined that the Company operates in one segment: the development of pharmaceutical products on its own behalf or in collaboration with others. The information included in this quarterly report on Form 10-Q should be read in conjunction with the Company’s consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 filed with the Securities and Exchange Commission on March 6, 2017. Use of Estimates and Summary of Significant Accounting Policies In preparing the condensed consolidated financial statements, management used estimates in the following areas, among others: revenue recognition for multiple-element revenue arrangements; stock-based compensation expense; income tax expense; accrued expenses; and the evaluation of the existence of conditions and events that raise substantial doubt regarding the Company’s ability to continue as a going concern. Actual results could differ from those estimates. There have been no material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standard Board, or FASB, issued Accounting Standards Update, or ASU, No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU 2014-09, which stipulates that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve this core principle, ASU 2014-09 provides that an entity should apply the following steps: (1) identify the contract(s) with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract and (5) recognize revenue when (or as) the entity satisfies a performance obligation. This update will be effective for the Company beginning in the first quarter of fiscal 2018 as a result of the FASB’s one year deferral of the effective date for this standard. The amendments may be applied retrospectively to each prior period (full retrospective) or retrospectively with the cumulative effect recognized as of the date of initial application (modified retrospective). Previously, the Company disclosed that it intended to apply ASU 2014-09 using the full retrospective approach. Due to the additional adoption efforts required of issuers under the full retrospective approach, the Company now intends to adopt ASU 2014-09 in the first quarter of 2018 using the modified retrospective approach. Under the modified retrospective approach, the cumulative effect of applying the standard would be recognized at the date of initial application within retained earnings. The Company is currently evaluating the effect of adopting the requirements of ASU 2014-09 as it relates to the accounting for its collaboration arrangements with Celgene Pharmaceuticals, Inc., Jazz Pharmaceuticals plc, Glaxo Group Limited and Avanir Pharmaceuticals, Inc., its patent assignment agreement with Auspex Pharmaceuticals, Inc., and its asset purchase agreement with Vertex Pharmaceuticals, Inc. The Company expects at a minimum that the accounting for contingent milestone payments that may be received under these collaboration agreements to change. Under ASU 2014-09, contingent milestone payments are treated as variable consideration in accordance with the overall model of ASU 2014-09. Revenue from contingent milestone payments may be recognized earlier under ASU 2014-09 than under the current revenue recognition standards, based on an assessment at each reporting date of the probability of achievement of the underlying milestone event. This assessment may, in certain circumstances, result in the recognition of revenue related to a contingent milestone payment before the milestone event has been achieved. In comparison to current revenue recognition standards, ASU 2014-09 also requires more robust disclosures, including disclosures related to disaggregation of revenue into appropriate categories, performance obligations, the judgments made in revenue recognition determinations, adjustments to revenue which relate to activities from previous quarters or years, any significant reversals of revenue, and costs to obtain or fulfill contracts. In connection with the adoption of ASU 2014-09, the Company is evaluating the need for additional internal controls, including controls to monitor the probability of achievement of contingent milestone payments and the pattern of performance of certain performance obligations. In August 2014, the FASB issued ASU No. 2014-15, Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern, or ASU 2014-15. ASU 2014-15 amends FASB Accounting Standards Codification, or ASC, 205-40, Presentation of Financial Statements – Going Concern, by providing guidance on determining when and how reporting entities must disclose going-concern uncertainties in their financial statements, including requiring management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date of issuance of the entity’s financial statements and providing certain disclosures if there is substantial doubt about the entity’s ability to continue as a going concern. The Company was required to apply the requirements of ASU 2014-15 in its interim financial statements beginning in the first quarter of fiscal 2017. With respect to the interim financial statements as of September 30, 2017, the Company did not identify any conditions or events that raise substantial doubt about its ability to continue as a going concern within one year after the date the financial statements are issued. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or ASU 2016-02. ASU 2016-02 requires lessees to recognize assets and liabilities on the balance sheet for the rights and obligations created by all leases with terms of more than 12 months. ASU 2016-02 also will require certain qualitative and quantitative disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. ASU 2016-02 will be effective for the Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the impact ASU 2016-02 will have on its financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation-Improvements to Employee Share-Based Payment Accounting, or ASU 2016-09. This update simplifies several aspects of the accounting for share-based compensation arrangements, including accounting for income taxes, forfeitures and statutory tax withholding requirements as well as classification of related amounts on the statement of cash flows. The Company adopted this ASU on January 1, 2017 and it did not have a material effect on the consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326)-Measurement of Credit Losses on Financial Instruments, or ASU 2016-13. The new standard requires entities to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. ASU 2016-13 will become effective for the Company for fiscal years beginning after December 15, 2019, with early adoption permitted. The Company is currently evaluating the impact ASU 2016-13 will have on its financial statements and related disclosures. In August 2016, the FASB issued ASU No. 2016-15—Classification of Certain Cash Receipts and Cash Payments. The amendments in ASU 2016-15 address eight specific cash flow issues and apply to all entities that are required to present a statement of cash flows under FASB Accounting Standards Codification (ASC) 230, Statement of Cash Flows. The amendments in ASU 2016-15 are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption during an interim period. The Company early adopted this update for the interim period ended September 30, 2017 as the treatment of debt extinguishment payments as a financing activity more clearly presents the cash outflow of the extinguishment transaction. No prior period amounts require retrospective adjustments as no debt extinguishments occurred in the prior year. The adoption of ASU 2016-15 resulted in classification of cash payments related to the debt prepayment as cash outflows for financing activities. Additional information concerning the prepayment of the Loan Agreement is discussed further in Note 11. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows - Restricted Cash (Topic 230). This new standard requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This guidance is effective for annual and interim reporting periods beginning after December 15, 2017, and requires retrospective application. The Company is currently assessing the impact that adopting ASU 2016-18 will have on its consolidated financial statements and related disclosures.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company has certain financial assets and liabilities that are recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements: • Level 1—quoted prices for identical instruments in active markets; • Level 2—quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets; and • Level 3—valuations derived from valuation techniques in which one or more significant value drivers are unobservable. The tables below present information about the Company’s financial assets and liabilities that are measured and carried at fair value as of September 30, 2017 and December 31, 2016 (in thousands) and indicate the level within the fair value hierarchy where each measurement is classified. Level 1 Level 2 Level 3 Total September 30, 2017 Cash equivalents: Money market funds $ 18,361 $ — $ — $ 18,361 U.S. Treasury obligations 4,998 — — 4,998 Investments, available for sale: U.S. Treasury obligations 58,771 — — 58,771 Government agency securities 73,151 43,071 — 116,222 Total $ 155,281 $ 43,071 $ — $ 198,352 Level 1 Level 2 Level 3 Total December 31, 2016 Cash equivalents: Money market funds $ 26,257 $ — $ — $ 26,257 U.S. Treasury obligations — 1,001 — 1,001 Investments, available for sale: U.S. Treasury obligations 10,034 5,503 — 15,537 Government agency securities 24,545 15,548 — 40,093 Total $ 60,836 $ 22,052 $ — $ 82,888

Cash, Cash Equivalents and Inve

Cash, Cash Equivalents and Investments	9 Months Ended
	Sep. 30, 2017
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Investments	Cash, Cash Equivalents and Investments Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase. Investments consist of securities with original maturities greater than 90 days when purchased. The Company classifies these investments as available-for-sale and records them at fair value in the accompanying consolidated balance sheets. Unrealized gains or losses are included in accumulated other comprehensive income (loss). Premiums or discounts from par value are amortized to investment income over the life of the underlying investment. Cash, cash equivalents and investments, available for sale included the following at September 30, 2017 and December 31, 2016: Average maturity Amortized cost Unrealized gains Unrealized losses Fair value September 30, 2017 Cash $ 8,760 $ — $ — $ 8,760 Money market funds 18,361 — — 18,361 U.S. Treasury obligations 19 days 4,998 — — 4,998 Cash and cash equivalents $ 32,119 $ — $ — $ 32,119 U.S. Treasury obligations 188 days 58,794 — (23 ) 58,771 Government agency securities 256 days 116,266 2 (46 ) 116,222 Investments, available for sale $ 175,060 $ 2 $ (69 ) $ 174,993 Average maturity Amortized cost Unrealized gains Unrealized losses Fair value December 31, 2016 Cash $ 13,297 $ — $ — $ 13,297 Money market funds 26,257 — — 26,257 U.S. Treasury obligations 31 days 1,001 — — 1,001 Cash and cash equivalents $ 40,555 $ — $ — $ 40,555 U.S. Treasury obligations 125 days 15,534 4 (1 ) 15,537 Government agency securities 140 days 40,103 1 (11 ) 40,093 Investments, available for sale $ 55,637 $ 5 $ (12 ) $ 55,630 Although available to be sold to meet operating needs or otherwise, securities are generally held through maturity. The cost of securities sold is determined based on the specific identification method for purposes of recording realized gains and losses. During 2017 and 2016, there were no realized gains or losses on sales of investments, and no investments were adjusted for other than temporary declines in fair value.

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	9 Months Ended
	Sep. 30, 2017
Payables and Accruals [Abstract]
Accrued Expenses and Other Liabilities	Accrued Expenses and Other Liabilities Accrued expenses and other liabilities consisted of the following: September 30, December 31, Accrued professional fees and other $ 507 $ 487 Employee compensation and benefits 1,810 2,010 Research and development expenses 615 930 Deferred lease incentive, current portion 331 324 Deferred rent, current portion 139 102 $ 3,402 $ 3,853

Asset Purchase Agreement

Asset Purchase Agreement	9 Months Ended
	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Asset Purchase Agreement	Asset Purchase Agreement On March 3, 2017, the Company and Vertex entered into an Asset Purchase Agreement pursuant to which, subject to the satisfaction or waiver of the conditions therein, the Company sold and assigned to Vertex, CTP-656, now known as VX-561, and other cystic fibrosis assets of the Company. On July 25, 2017, the Asset Purchase Agreement closed and Vertex paid the Company $160 million in cash consideration, with $16 million to initially be held in escrow. There are no refund provisions with the exception of the amount held in escrow for potential indemnification for a period of eighteen months . Additionally, upon the achievement of certain milestone events, Vertex has agreed to pay the Company an aggregate of up to $90 million . Of this amount, $50 million will become payable to the Company upon receipt of FDA marketing approval for a combination treatment regimen containing CTP-656, now known as VX-561, for patients with cystic fibrosis, and $40 million will become payable to the Company upon completion of a pricing and reimbursement agreement in the first of the United Kingdom, Germany or France with respect to a combination treatment regimen containing CTP-656 for patients with cystic fibrosis. Pursuant to the Asset Purchase Agreement, the Company has agreed to indemnify Vertex for certain matters, including breaches of specified representations and warranties, covenants included in the Asset Purchase Agreement and specified tax claims. Representations and warranties, other than certain fundamental representations and warranties, survive for a period of eighteen months following the Closing and the maximum liability of the Company for claims by Vertex related to the breaches of such representations and warranties, with limited exceptions, is limited to the escrow amount, or $16 million . In no event will the aggregate liability of the Company for indemnification exceed the purchase price paid by Vertex, including any milestone payments. Eighteen months after the Closing, any remaining balance in the escrow account not subject to indemnity claims by Vertex will be released to the Company. The Asset Purchase Agreement with Vertex contains the following deliverables: (i) all rights to develop, manufacture, and commercialize deuterated analogs of Kalydeco related to the CTP-656 program, including all intellectual property, permits and registrations, and records, documentation, and regulatory filings, in addition to an obligation to perform research and testing consulting services to facilitate the transfer of materials, documents, and knowledge up to the close of the Asset Purchase Agreement, referred to as the Transfer of IP Deliverable, and (ii) an obligation to perform certain limited transition services including manufacturing, clinical, regulatory, quality assurance, and intellectual property consulting subsequent to the close of the Asset Purchase Agreement to expedite the advancement of CTP-656 without impacting Vertex’s development timeline, referred to as the Transition Services Deliverable. The Company concluded that the Transfer of IP Deliverable has standalone value because Vertex can fully utilize the underlying intellectual property for its intended purpose without the Transition Services Deliverable. This conclusion considered Vertex's expertise as it relates to the clinical development and manufacturing of cystic fibrosis products that enable Vertex to use the intellectual property for its intended purpose without involvement of the Company. The purpose of the Transition Services Deliverable is to transfer ongoing manufacturing and clinical activities to Vertex and do not otherwise represent Company know-how. Accordingly, each deliverable qualifies as a separate unit of accounting. The Company determined that neither vendor specific objective evidence (VSOE) of selling price nor third party evidence (TPE) of selling price was available for any of the units of accounting identified as the inception of the arrangement with Vertex. Accordingly, the selling price of each unit of accounting was determined based on the Company's best estimate of selling price (BESP). The Company developed its BESP for the intellectual property under the Transfer of IP Deliverable through a risk adjusted discounted cash flow model of the CTP-656 asset that considered applicable market conditions, probabilities of technical success, relevant entity-specific factors, and factors contemplated in negotiating the agreement. The Company developed BESP for the research and testing consulting services included under the Transfer of IP Deliverable and the services included under the Transition Services Deliverable based on the nature of services to be performed, estimates of the associated effort, and cost of the services adjusted for a reasonable profit margin such that they represented estimated market rates for similar services on standalone basis. Allocable arrangement consideration at inception was limited to the $144.1 million non-refundable upfront payment. Total allocable arrangement consideration was allocated among the separate units of accounting using the relative selling price method as follows: (i) $143.7 million to the Transfer of IP Deliverable; and (ii) $0.4 million to the Transition Services Deliverable. Given the significant value of the intellectual property under the Transfer of IP Deliverable relative to the limited transition services under the Transition Services Deliverable, changes in the BESP of the intellectual property would not result in a significant change in allocation. The arrangement consideration allocated to the Transfer of IP Deliverable was recognized upon the close of the Asset Purchase Agreement as all items under that deliverable were delivered on the closing date, whereas amounts allocated to the Transition Services Deliverable are recognized under the proportional performance method over the expected period of performance. The Company has evaluated each of the milestones that may be received in connection with the Asset Purchase Agreement. Each of the milestones are considered substantive on the basis of the contingent nature of the milestone, specifically reviewing factors such as the scientific, clinical, regulatory and other risks that must be overcome to achieve the milestone as well as the level of effort and investment required. Accordingly, such amounts will be recognized as revenue in full in the period in which the associated milestone is achieved, assuming all other revenue recognition criteria are met. As of September 30, 2017, the Company recognized $143.8 million in revenue with $0.3 million remaining in deferred revenue subject to the completion of transition services provided to Vertex pursuant to the Asset Purchase Agreement.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. The Company’s ability to use its operating loss carryforwards and tax credits to offset future taxable income is subject to restrictions under Sections 382 and 383 of the United States Internal Revenue Code (the “Internal Revenue Code”). Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50 percent, as defined under Sections 382 and 383 of the Internal Revenue Code. Such changes would limit the Company’s use of its operating loss carryforwards and tax credits. In such a situation, the Company may be required to pay income taxes, even though significant operating loss carryforwards and tax credits exist. The Company expects to have sufficient operating loss carryforwards and tax credits to offset substantially all of the taxable income generated during fiscal year 2017 as a result of the closing of the Asset Purchase Agreement in Note 6. The Company records a provision or benefit for income taxes on ordinary pre-tax income or loss based on its estimated effective tax rate for the year. As of September 30, 2017, the Company forecasts pre-tax income for the year ended December 31, 2017 as a result of the closing of the Asset Purchase Agreement during the period. The Company recorded $2.2 million in income tax expense during the three and nine months ended September 30, 2017 in connection with the federal limitation on alternative minimum tax net operating loss carryforwards, which limits the use of net operating loss carryforwards to ninety percent of alternative minimum taxable income and results in an effective tax rate of approximately two percent for 2017.

Collaborations

Collaborations	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborations	Collaborations Celgene In April 2013, the Company entered into a master development and license agreement with Celgene Corporation and Celgene International Sàrl, referred to together as Celgene, which is primarily focused on the research, development and commercialization of specified deuterated compounds targeting inflammation or cancer. The initial program in the collaboration is CTP-730, a deuterium-modified analog of apremilast. Celgene has an exclusive worldwide license to develop, manufacture and commercialize deuterated analogs of apremilast and certain close chemical derivatives thereof. The Company further granted Celgene licenses with respect to two additional programs and an option with respect to a third additional program. The Company was responsible for conducting and funding research and early development activities for the CTP-730 program at its own expense pursuant to mutually agreed upon development plans. This included the completion of single and multiple ascending dose Phase 1 clinical trials in 2015. Under the terms of the agreement, the Company received a non-refundable upfront payment of $35.0 million . In October 2015, the Company earned and recognized as milestone revenue an $8.0 million development milestone based on the completion of Phase 1 clinical evaluation of CTP-730. In addition, the Company is eligible to earn an additional $15.0 million development milestone payment, up to $247.5 million in regulatory milestone payments and up to $50.0 million in sales-based milestone payments related to products within the CTP-730 program. The next milestone payment the Company may be entitled to achieve under the CTP-730 program is $15.0 million related to the first actual dosing in a Phase 3 clinical trial or, if earlier, acceptance for filing of a new drug application, or NDA. If Celgene exercises its rights with respect to either of the two additional license programs, the Company will receive a license exercise fee for the applicable program of $30.0 million and will also be eligible to earn up to $23.0 million in development milestone payments and up to $247.5 million in regulatory milestone payments for that program. Additionally, with respect to one of the additional license programs, the Company is eligible to receive up to $100.0 million in milestone payments based on net sales of products, and with respect to the other additional license program, the Company is eligible to receive up to $50.0 million in milestone payments based on net sales of products. If Celgene exercises its option with respect to the option program, in respect of a compound to be identified at a later time, the Company will receive an option exercise fee of $10.0 million and will be eligible to earn up to $23.0 million in development milestone payments and up to $247.5 million in regulatory milestone payments. In addition, with respect to each program, Celgene is required to pay the Company royalties on worldwide net sales of each licensed product at defined percentages ranging from the mid-single digits to low double digits below 20% . The royalty rate is reduced on a country-by-country basis during any period within the royalty term when there is no patent claim or regulatory exclusivity covering the licensed product in the particular country. During the three months ended September 30, 2017, the Company recognized revenue of $8 thousand for the R&D Services and Supply Deliverables, as compared to the $9 thousand recognized during the three months ended September 30, 2016. During the nine months ended September 30, 2017 and 2016, the Company recognized revenue of $20 thousand and $68 thousand for the R&D Services and Supply Deliverables, respectively. The revenue was classified as license and research and development revenue in the accompanying condensed consolidated statements of operations and comprehensive income (loss). As of September 30, 2017, there was $7.2 million of deferred revenue related to the Company’s collaboration with Celgene, $1.1 million of which was classified as a current liability and $6.1 million o f which was classified as a noncurrent liability, in the accompanying condensed consolidated balance sheet. Jazz Pharmaceuticals In February 2013, the Company entered into a development and license agreement with Jazz Pharmaceuticals, Inc., or Jazz Pharmaceuticals, to research, develop and commercialize products containing a deuterated sodium oxybate analog, or D-SXB. Jazz Pharmaceuticals is initially focusing on one analog, designated as JZP-386. Under the terms of the agreement, the Company granted Jazz Pharmaceuticals an exclusive, worldwide, royalty-bearing license under intellectual property controlled by the Company to develop, manufacture and commercialize D-SXB products including, but not limited to, JZP-386. The Company, together with Jazz Pharmaceuticals, has conducted certain development activities for Phase 1 clinical trials with respect to JZP-386 pursuant to an agreed upon development plan. The Company was responsible under the development plan for conducting the Phase 1 clinical trials with respect to JZP-386. The Company’s obligations to conduct further development activities are subject to mutual agreement. Jazz Pharmaceuticals has assumed all manufacturing and development responsibilities relating to JZP-386. Pursuant to the agreement, the Company’s costs for activities under the development plan were reimbursed by Jazz Pharmaceuticals, except for the costs of a Phase 1 clinical trial that was conducted in the first half of 2015, which was shared between Jazz Pharmaceuticals and the Company. Under the agreement, the Company received a non-refundable upfront payment of $4.0 million and is eligible to earn an aggregate of up to $8.0 million in development milestone payments, up to $35.0 million in regulatory milestone payments and up to $70.0 million in sales-based milestone payments based on net product sales of licensed products. The next milestone payment that the Company may be entitled to receive is $4.0 million related to initiation of the first Phase 2 clinical trial of JZP-386. In addition, Jazz Pharmaceuticals is required to pay the Company royalties at defined percentages ranging from the mid-single digits to low double digits below 20% on worldwide net sales of licensed products. The royalty rate is lowered, on a country-by-country basis, under certain circumstances as specified in the agreement. For the three months ended September 30, 2017 and 2016, the Company recognized revenue of $9 thousand and $18 thousand respectively, related to the performance of development support services. For the nine months ended September 30, 2017 and 2016, the Company recognized revenue of $31 thousand and $86 thousand related to the performance of development support services, respectively. Avanir In February 2012, the Company entered into a development and license agreement with Avanir Pharmaceuticals, Inc., or Avanir, under which the Company granted Avanir an exclusive worldwide license to develop, manufacture and commercialize deudextromethorphan containing products. Avanir is currently focused on developing AVP-786, which is a combination of a deudextromethorphan and an ultra low dose of quinidine. Subsequent to the Company’s agreement, Avanir was acquired by Otsuka Pharmaceutical Co., Ltd. and it is now a wholly owned subsidiary of Otsuka America, Inc. Since June 2012, Avanir has elected to conduct all research and development activities, including manufacturing activities; however, the Company has received intellectual property cost reimbursements. Under the agreement, the Company received a non-refundable upfront payment of $2.0 million and has received milestone payments of $6.0 million . The Company is also eligible to earn, with respect to licensed products comprising a combination of deudextromethorphan and quinidine, up to $37.0 million in regulatory and commercial launch milestone payments, of which $21.5 million in development and regulatory milestone payments are associated with the first indication, and up to $125.0 million in sales-based milestone payments. The next milestone payments that the Company may be entitled to receive are $5.0 million upon acceptance for filing of a NDA, $3.0 million upon acceptance for filing of a Marketing Authorization Application, or MAA, and $1.5 million upon acceptance for filing of a NDA by the Ministry of Health, Labour and Welfare, or MHLW, related to AVP-786. In addition, the Company is eligible for higher development milestones, up to an additional $43.0 million , for licensed products that do not require quinidine. Avanir is currently developing deudextromethorphan only in combination with quinidine. Avanir also is required to pay the Company royalties at defined percentages ranging from the mid-single digits to low double digits below 20% on net sales of licensed products on a country-by-country basis. The royalty rate is reduced, on a country-by-country basis, during any period within the royalty term when there is no patent claim covering the licensed product in the particular country.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company’s equity incentive plans provide for the issuance of a variety of stock-based awards, including incentive stock options, nonstatutory stock options and awards of stock, to directors, officers and employees of the Company, as well as consultants and advisors to the Company. As of September 30, 2017, the Company has granted awards in the form of stock options and restricted stock units (the "RSUs"). The stock options generally have been granted with an exercise price equal to the fair value of the underlying common stock on the date of grant, a vesting period of three or four years, and all options expire no later than ten years from the date of grant. Effective January 1, 2017, an additional 892,679 shares were added to the Company’s 2014 Stock Incentive Plan, or the 2014 Plan, for future issuance pursuant to the terms of the 2014 Plan. As of September 30, 2017, there were 1,191,572 shares of common stock available for future award grants under the 2014 Plan. Total stock-based compensation expense related to all stock-based options and awards recognized in the condensed consolidated statements of operations and comprehensive income (loss) consisted of: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Research and development $ 1,105 $ 532 $ 2,507 $ 1,638 General and administrative 1,392 730 3,206 2,193 Total stock-based compensation expense $ 2,497 $ 1,262 $ 5,713 $ 3,831 Stock Options Stock options are valued using the Black-Scholes-Merton option valuation model and compensation cost is recognized based on such fair value over the period of vesting. The weighted average fair value of options granted in the three and nine months ended September 30, 2017 and 2016 reflect the following weighted-average assumptions: Three Months Ended Nine Months Ended September 30, 2017 2016 2017 2016 Expected volatility 77.34 % 78.07 % 78.15 % 78.29 % Expected term 6.0 years 6.0 years 6.0 years 6.0 years Risk-free interest rate 2.04 % 1.28 % 2.07 % 1.35 % Expected dividend yield — % — % — % — % For the three and nine months ended September 30, 2017, expected volatility was estimated using a weighted-average of the Company's historical volatility of its common stock and the historical volatility of the common stock of a group of similar companies that were publicly traded. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. For the three and nine months ended September 30, 2016, expected volatility was estimated using the historical volatility of the common stock of a group of similar companies that were publicly traded. The following table provides certain information related to the Company's outstanding stock options: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands, except per share data) Weighted average grant date fair value of options granted, per option $ 9.51 $ 6.75 $ 7.67 $ 10.47 Aggregate grant date fair value of options vested during the period $ 1,634 $ 1,143 $ 4,601 $ 3,527 Total cash received from exercises of stock options $ 939 $ 54 $ 2,396 $ 293 Total intrinsic value of stock options exercised $ 1,052 $ 101 $ 4,361 $ 729 The following is a summary of stock option activity for the nine months ended September 30, 2017: Number of Option Shares Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (In years) (In thousands) Outstanding at December 31, 2016 2,953,961 $ 10.49 Granted 1,065,500 $ 11.25 Exercised (436,531 ) $ 5.57 Forfeited or expired (183,442 ) $ 12.39 Outstanding at September 30, 2017 3,399,488 $ 11.25 6.57 $ 13,434 Exercisable at September 30, 2017 1,804,330 $ 10.03 5.44 $ 9,170 Vested and expected to vest at September 30, 2017 (1) 3,260,214 $ 11.20 6.51 $ 13,042 (1) This represents the number of vested stock option shares as of September 30, 2017, plus the number of unvested stock option shares that the Company estimated as of September 30, 2017 would vest, based on the unvested stock option shares at September 30, 2017 and an estimated forfeiture rate of 7% . As of September 30, 2017, there was $11.4 million of unrecognized compensation cost related to stock options that are expected to vest. The stock option costs are expected to be recognized over a weighted average remaining vesting period of 2.5 years. Restricted Stock Units On July 6, 2017, the Company granted 0.5 million RSUs to executives and employees. The awards granted to employees are service-based whereas the awards granted to executives are a blend of service-based and performance-based. Assuming all service and performance conditions are achieved, fifty percent of the RSUs will vest on March 31, 2018, and the remaining fifty percent of the RSUs will vest on March 31, 2019. Certain executive awards are subject to the achievement of defined performance criteria prior to March 31, 2018, including the closing of the Asset Purchase Agreement with Vertex Pharmaceuticals, Inc. and the institution by the Patent Trial and Appeal Board ("PTAB") of the Post Grant Review ("PGR") petition filed by the Company against Incyte Corporation. The Company is using the accelerated attribution method to recognize expense over the required service period based on its estimate of the number of performance-based awards that will vest. If there is a change in the estimate of the number of performance-based awards that are probable of vesting, the Company will cumulatively adjust compensation expense in the period that the change in estimate is made. RSUs are not included in issued and outstanding common stock until the shares are vested and released. As of September 30, 2017, no RSUs had vested. The fair value of an RSU is measured based on the market price of the underlying common stock as of the date of grant, reduced by the purchase price of $0.001 per share. For the three and nine months ended September 30, 2017, the weighted-average grant date fair value of RSUs is $13.87 . The following is a summary of RSU activity, including both time-based and performance-based restricted stock units for the nine months ended September 30, 2017: Number of RSU Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2016 — $ — Granted 520,500 $ 13.87 Released — $ — Forfeited — $ — Outstanding at September 30, 2017 520,500 $ 13.87 As of September 30, 2017, there was $4.9 million of unrecognized compensation cost related to restricted stock units that are expected to vest. This amount excludes compensation cost related to restricted stock units where the performance conditions are not considered probable of being satisfied. The costs from restricted stock units likely to vest are expected to be recognized over a weighted average remaining vesting period of 1.2 years.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share The Company has outstanding warrants, including those issued in connection with the Loan and Security Agreement described in Note 11, that are deemed to be participating securities. Accordingly, the Company applied the two-class method to calculate basic and diluted net earnings per share of common stock for the three and nine months ended September 30, 2017. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to common stockholders. The two-class method was not applied for the three and nine months ended September 30, 2016 as the Company’s participating securities do not have any obligation to absorb net losses. Basic net earnings (loss) per common share is calculated by dividing net income (loss) allocable to common stockholders by the weighted-average common shares outstanding during the period, without consideration of common stock equivalents. For periods with net income, diluted net earnings per share is calculated by either (i) adjusting the weighted-average shares outstanding for the dilutive effect of common stock equivalents, including warrants, stock options and restricted stock units outstanding for the period as determined using the treasury stock method or (ii) the two-class method considering common stock equivalents, whichever is more dilutive. For purposes of the diluted net loss per share calculation, common stock equivalents are excluded from the calculation if their effect would be anti-dilutive. As such, basic and diluted net loss per share applicable to common stockholders are the same for periods with a net loss. The following table illustrates the determination of earnings (loss) per share for each period presented. Three Months Ended September 30, Nine Months Ended 2017 2016 2017 2016 Basic Earnings per Share: (in thousands, expect per share amounts) Numerator: Net income (loss) $ 128,065 $ (11,356 ) $ 101,705 $ (38,677 ) Income attributable to participating securities - basic 741 — 433 — Income (loss) attributable to common stockholders - basic 127,324 (11,356 ) 101,272 (38,677 ) Denominator: Weighted average shares outstanding 22,694 22,229 22,551 22,215 Net income (loss) per share applicable to common stockholders - basic $ 5.61 $ (0.51 ) $ 4.49 $ (1.74 ) Diluted Earnings per Share: Numerator: Net income (loss) $ 128,065 $ (11,356 ) $ 101,705 $ (38,677 ) Income attributable to participating securities - diluted 718 — 421 — Income (loss) attributable to common stockholders - diluted 127,347 (11,356 ) 101,284 (38,677 ) Denominator: Weighted average shares outstanding 22,694 22,229 22,551 22,215 Dilutive impact from: Stock options 585 — 602 — Restricted stock units 142 — 42 — Weighted average shares outstanding - diluted 23,421 22,229 23,195 22,215 Net income (loss) per share applicable to common stockholders - diluted $ 5.44 $ (0.51 ) $ 4.37 $ (1.74 ) Anti-dilutive potential common stock equivalents excluded from the calculation of net income (loss) per share: Stock options 2,172 571 2,235 668 Restricted stock units 379 — 479 — Warrants — 71 — 71

Loan Payable and Warrant to Pur

Loan Payable and Warrant to Purchase Common Stock	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Loan Payable and Warrant to Purchase Common Stock	Loan Payable and Warrant to Purchase Common Stock On June 8, 2017, the Company entered into a Loan Agreement with Hercules, pursuant to which Hercules agreed to make available to the Company a Term Loan Facility in the amount of $30.0 million , subject to certain terms and conditions. The Company borrowed $30.0 million under the Loan Agreement in one advance. The Company incurred $0.3 million in loan issuance costs paid directly to the lenders, which was offset against the loan proceeds as a loan discount. The advance under the Loan and Security Agreement bore interest at a variable rate of the greater of 8.55% and an amount equal to 8.55% plus the prime rate of interest minus 4.50% . Through September 7, 2017, the Term Loan Facility had an interest rate of 8.55% . Pursuant to the Loan Agreement, the Company had the option to prepay the principal of the Loan Agreement at any time subject to a prepayment charge; however the prepayment charge was waived upon the completion of the sale of CTP-656 to Vertex, discussed further in Note 6, and the prepayment of the Term Loan Facility after the 90 th day following the closing date of the Loan Agreement but prior to the six month anniversary of the closing date of the Loan Agreement. On September 7, 2017, the Company paid a total of $30.8 million to Hercules, representing the principal, accrued and unpaid interest, fees, costs and expenses outstanding under the Loan Agreement. The payoff amount included a final end of term charge to Hercules in the amount of $0.7 million , reduced from the $1.5 million end of term charge required had the debt been held to maturity. Upon the payment of the $30.8 million pursuant to a payoff letter between the Company and Hercules, all outstanding indebtedness and obligations of the Company owed to Hercules under the Loan Agreement were paid in full, and the Loan Agreement was terminated. As a result of the debt extinguishment, the Company recognized a loss of $1.4 million during the quarter ended September 30, 2017. In connection with the entry into the Loan Agreement, the Company issued warrants (the "Warrants") to certain entities affiliated with Hercules, exercisable for an aggregate of 61,273 shares of the Company’s common stock at an exercise price of $12.24 per share. The Warrants have a five year term, expiring June 8, 2022, and may be exercised on a cashless basis. The Hercules Warrants had a total relative fair value of $0.5 million upon issuance and were recorded as a debt discount. Pursuant to ASC Topic 480, Distinguishing Liabilities from Equity and ASC Topic 815, Derivatives and Hedging , the Warrants were classified as equity and were initially measured at relative fair value. Subsequent changes to fair value will not be recognized so long as the instrument continues to be equity classified. To determine the relative fair value, the Company measured the fair value of the Warrants as of June 8, 2017 using the Black-Scholes-Merton option pricing model. The significant assumptions used in estimating the fair value of the Warrants include the volatility of the stock underlying the warrants, risk-free interest rate, and estimated life of the warrant. The Company used the following weighted-average assumptions: Expected volatility 73.71 % Expected term (in years) 5 Risk-free interest rate 1.75 % Expected dividend yield — % Consistent with the Company’s weighted-average assumptions used in determining the fair value of options, expected volatility was estimated using a weighted-average of the Company's historical volatility of its common stock and the historical volatility of the common stock of a group of similar companies that were publicly traded.

Basis of Presentation and Sig17

Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments, consisting of normal recurring accruals and revisions of estimates, considered necessary for a fair presentation of the condensed consolidated financial statements have been included. Interim results for the three and nine months ended September 30, 2017 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2017 or any other future period. The accompanying condensed consolidated financial statements reflect the accounts of Concert and its subsidiaries. All intercompany transactions between the Company and its subsidiaries have been eliminated. Management has determined that the Company operates in one segment: the development of pharmaceutical products on its own behalf or in collaboration with others. The information included in this quarterly report on Form 10-Q should be read in conjunction with the Company’s consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 filed with the Securities and Exchange Commission on March 6, 2017.
Use of Estimates and Summary of Significant Accounting Policies	Use of Estimates and Summary of Significant Accounting Policies In preparing the condensed consolidated financial statements, management used estimates in the following areas, among others: revenue recognition for multiple-element revenue arrangements; stock-based compensation expense; income tax expense; accrued expenses; and the evaluation of the existence of conditions and events that raise substantial doubt regarding the Company’s ability to continue as a going concern. Actual results could differ from those estimates. There have been no material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standard Board, or FASB, issued Accounting Standards Update, or ASU, No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU 2014-09, which stipulates that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve this core principle, ASU 2014-09 provides that an entity should apply the following steps: (1) identify the contract(s) with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract and (5) recognize revenue when (or as) the entity satisfies a performance obligation. This update will be effective for the Company beginning in the first quarter of fiscal 2018 as a result of the FASB’s one year deferral of the effective date for this standard. The amendments may be applied retrospectively to each prior period (full retrospective) or retrospectively with the cumulative effect recognized as of the date of initial application (modified retrospective). Previously, the Company disclosed that it intended to apply ASU 2014-09 using the full retrospective approach. Due to the additional adoption efforts required of issuers under the full retrospective approach, the Company now intends to adopt ASU 2014-09 in the first quarter of 2018 using the modified retrospective approach. Under the modified retrospective approach, the cumulative effect of applying the standard would be recognized at the date of initial application within retained earnings. The Company is currently evaluating the effect of adopting the requirements of ASU 2014-09 as it relates to the accounting for its collaboration arrangements with Celgene Pharmaceuticals, Inc., Jazz Pharmaceuticals plc, Glaxo Group Limited and Avanir Pharmaceuticals, Inc., its patent assignment agreement with Auspex Pharmaceuticals, Inc., and its asset purchase agreement with Vertex Pharmaceuticals, Inc. The Company expects at a minimum that the accounting for contingent milestone payments that may be received under these collaboration agreements to change. Under ASU 2014-09, contingent milestone payments are treated as variable consideration in accordance with the overall model of ASU 2014-09. Revenue from contingent milestone payments may be recognized earlier under ASU 2014-09 than under the current revenue recognition standards, based on an assessment at each reporting date of the probability of achievement of the underlying milestone event. This assessment may, in certain circumstances, result in the recognition of revenue related to a contingent milestone payment before the milestone event has been achieved. In comparison to current revenue recognition standards, ASU 2014-09 also requires more robust disclosures, including disclosures related to disaggregation of revenue into appropriate categories, performance obligations, the judgments made in revenue recognition determinations, adjustments to revenue which relate to activities from previous quarters or years, any significant reversals of revenue, and costs to obtain or fulfill contracts. In connection with the adoption of ASU 2014-09, the Company is evaluating the need for additional internal controls, including controls to monitor the probability of achievement of contingent milestone payments and the pattern of performance of certain performance obligations. In August 2014, the FASB issued ASU No. 2014-15, Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern, or ASU 2014-15. ASU 2014-15 amends FASB Accounting Standards Codification, or ASC, 205-40, Presentation of Financial Statements – Going Concern, by providing guidance on determining when and how reporting entities must disclose going-concern uncertainties in their financial statements, including requiring management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date of issuance of the entity’s financial statements and providing certain disclosures if there is substantial doubt about the entity’s ability to continue as a going concern. The Company was required to apply the requirements of ASU 2014-15 in its interim financial statements beginning in the first quarter of fiscal 2017. With respect to the interim financial statements as of September 30, 2017, the Company did not identify any conditions or events that raise substantial doubt about its ability to continue as a going concern within one year after the date the financial statements are issued. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or ASU 2016-02. ASU 2016-02 requires lessees to recognize assets and liabilities on the balance sheet for the rights and obligations created by all leases with terms of more than 12 months. ASU 2016-02 also will require certain qualitative and quantitative disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. ASU 2016-02 will be effective for the Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the impact ASU 2016-02 will have on its financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation-Improvements to Employee Share-Based Payment Accounting, or ASU 2016-09. This update simplifies several aspects of the accounting for share-based compensation arrangements, including accounting for income taxes, forfeitures and statutory tax withholding requirements as well as classification of related amounts on the statement of cash flows. The Company adopted this ASU on January 1, 2017 and it did not have a material effect on the consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326)-Measurement of Credit Losses on Financial Instruments, or ASU 2016-13. The new standard requires entities to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. ASU 2016-13 will become effective for the Company for fiscal years beginning after December 15, 2019, with early adoption permitted. The Company is currently evaluating the impact ASU 2016-13 will have on its financial statements and related disclosures. In August 2016, the FASB issued ASU No. 2016-15—Classification of Certain Cash Receipts and Cash Payments. The amendments in ASU 2016-15 address eight specific cash flow issues and apply to all entities that are required to present a statement of cash flows under FASB Accounting Standards Codification (ASC) 230, Statement of Cash Flows. The amendments in ASU 2016-15 are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption during an interim period. The Company early adopted this update for the interim period ended September 30, 2017 as the treatment of debt extinguishment payments as a financing activity more clearly presents the cash outflow of the extinguishment transaction. No prior period amounts require retrospective adjustments as no debt extinguishments occurred in the prior year. The adoption of ASU 2016-15 resulted in classification of cash payments related to the debt prepayment as cash outflows for financing activities. Additional information concerning the prepayment of the Loan Agreement is discussed further in Note 11. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows - Restricted Cash (Topic 230). This new standard requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This guidance is effective for annual and interim reporting periods beginning after December 15, 2017, and requires retrospective application. The Company is currently assessing the impact that adopting ASU 2016-18 will have on its consolidated financial statements and related disclosures.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Recognized at Fair Value	The tables below present information about the Company’s financial assets and liabilities that are measured and carried at fair value as of September 30, 2017 and December 31, 2016 (in thousands) and indicate the level within the fair value hierarchy where each measurement is classified. Level 1 Level 2 Level 3 Total September 30, 2017 Cash equivalents: Money market funds $ 18,361 $ — $ — $ 18,361 U.S. Treasury obligations 4,998 — — 4,998 Investments, available for sale: U.S. Treasury obligations 58,771 — — 58,771 Government agency securities 73,151 43,071 — 116,222 Total $ 155,281 $ 43,071 $ — $ 198,352 Level 1 Level 2 Level 3 Total December 31, 2016 Cash equivalents: Money market funds $ 26,257 $ — $ — $ 26,257 U.S. Treasury obligations — 1,001 — 1,001 Investments, available for sale: U.S. Treasury obligations 10,034 5,503 — 15,537 Government agency securities 24,545 15,548 — 40,093 Total $ 60,836 $ 22,052 $ — $ 82,888

Cash, Cash Equivalents and In19

Cash, Cash Equivalents and Investments (Tables)	9 Months Ended
	Sep. 30, 2017
Cash and Cash Equivalents [Abstract]
Cash Equivalents and Short-term and Long-term Investments	Cash, cash equivalents and investments, available for sale included the following at September 30, 2017 and December 31, 2016: Average maturity Amortized cost Unrealized gains Unrealized losses Fair value September 30, 2017 Cash $ 8,760 $ — $ — $ 8,760 Money market funds 18,361 — — 18,361 U.S. Treasury obligations 19 days 4,998 — — 4,998 Cash and cash equivalents $ 32,119 $ — $ — $ 32,119 U.S. Treasury obligations 188 days 58,794 — (23 ) 58,771 Government agency securities 256 days 116,266 2 (46 ) 116,222 Investments, available for sale $ 175,060 $ 2 $ (69 ) $ 174,993 Average maturity Amortized cost Unrealized gains Unrealized losses Fair value December 31, 2016 Cash $ 13,297 $ — $ — $ 13,297 Money market funds 26,257 — — 26,257 U.S. Treasury obligations 31 days 1,001 — — 1,001 Cash and cash equivalents $ 40,555 $ — $ — $ 40,555 U.S. Treasury obligations 125 days 15,534 4 (1 ) 15,537 Government agency securities 140 days 40,103 1 (11 ) 40,093 Investments, available for sale $ 55,637 $ 5 $ (12 ) $ 55,630

Accrued Expenses and Other Li20

Accrued Expenses and Other Liabilities (Tables)	9 Months Ended
	Sep. 30, 2017
Payables and Accruals [Abstract]
Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities consisted of the following: September 30, December 31, Accrued professional fees and other $ 507 $ 487 Employee compensation and benefits 1,810 2,010 Research and development expenses 615 930 Deferred lease incentive, current portion 331 324 Deferred rent, current portion 139 102 $ 3,402 $ 3,853

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense Related to All Stock Based Awards Recognized in Statements of Operations and Comprehensive Income (Loss)	Total stock-based compensation expense related to all stock-based options and awards recognized in the condensed consolidated statements of operations and comprehensive income (loss) consisted of: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Research and development $ 1,105 $ 532 $ 2,507 $ 1,638 General and administrative 1,392 730 3,206 2,193 Total stock-based compensation expense $ 2,497 $ 1,262 $ 5,713 $ 3,831
Estimated Weighted-Average Assumptions of Options Granted	The weighted average fair value of options granted in the three and nine months ended September 30, 2017 and 2016 reflect the following weighted-average assumptions: Three Months Ended Nine Months Ended September 30, 2017 2016 2017 2016 Expected volatility 77.34 % 78.07 % 78.15 % 78.29 % Expected term 6.0 years 6.0 years 6.0 years 6.0 years Risk-free interest rate 2.04 % 1.28 % 2.07 % 1.35 % Expected dividend yield — % — % — % — %
Certain Information Related to Outstanding Stock Options	The following table provides certain information related to the Company's outstanding stock options: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (in thousands, except per share data) Weighted average grant date fair value of options granted, per option $ 9.51 $ 6.75 $ 7.67 $ 10.47 Aggregate grant date fair value of options vested during the period $ 1,634 $ 1,143 $ 4,601 $ 3,527 Total cash received from exercises of stock options $ 939 $ 54 $ 2,396 $ 293 Total intrinsic value of stock options exercised $ 1,052 $ 101 $ 4,361 $ 729
Summary of Stock Option Activity	The following is a summary of stock option activity for the nine months ended September 30, 2017: Number of Option Shares Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (In years) (In thousands) Outstanding at December 31, 2016 2,953,961 $ 10.49 Granted 1,065,500 $ 11.25 Exercised (436,531 ) $ 5.57 Forfeited or expired (183,442 ) $ 12.39 Outstanding at September 30, 2017 3,399,488 $ 11.25 6.57 $ 13,434 Exercisable at September 30, 2017 1,804,330 $ 10.03 5.44 $ 9,170 Vested and expected to vest at September 30, 2017 (1) 3,260,214 $ 11.20 6.51 $ 13,042 (1) This represents the number of vested stock option shares as of September 30, 2017, plus the number of unvested stock option shares that the Company estimated as of September 30, 2017 would vest, based on the unvested stock option shares at September 30, 2017 and an estimated forfeiture rate of 7% .
Summary of RSU Activity	The following is a summary of RSU activity, including both time-based and performance-based restricted stock units for the nine months ended September 30, 2017: Number of RSU Shares Weighted Average Grant Date Fair Value Outstanding at December 31, 2016 — $ — Granted 520,500 $ 13.87 Released — $ — Forfeited — $ — Outstanding at September 30, 2017 520,500 $ 13.87

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings (Loss) Per Share	The following table illustrates the determination of earnings (loss) per share for each period presented. Three Months Ended September 30, Nine Months Ended 2017 2016 2017 2016 Basic Earnings per Share: (in thousands, expect per share amounts) Numerator: Net income (loss) $ 128,065 $ (11,356 ) $ 101,705 $ (38,677 ) Income attributable to participating securities - basic 741 — 433 — Income (loss) attributable to common stockholders - basic 127,324 (11,356 ) 101,272 (38,677 ) Denominator: Weighted average shares outstanding 22,694 22,229 22,551 22,215 Net income (loss) per share applicable to common stockholders - basic $ 5.61 $ (0.51 ) $ 4.49 $ (1.74 ) Diluted Earnings per Share: Numerator: Net income (loss) $ 128,065 $ (11,356 ) $ 101,705 $ (38,677 ) Income attributable to participating securities - diluted 718 — 421 — Income (loss) attributable to common stockholders - diluted 127,347 (11,356 ) 101,284 (38,677 ) Denominator: Weighted average shares outstanding 22,694 22,229 22,551 22,215 Dilutive impact from: Stock options 585 — 602 — Restricted stock units 142 — 42 — Weighted average shares outstanding - diluted 23,421 22,229 23,195 22,215 Net income (loss) per share applicable to common stockholders - diluted $ 5.44 $ (0.51 ) $ 4.37 $ (1.74 ) Anti-dilutive potential common stock equivalents excluded from the calculation of net income (loss) per share: Stock options 2,172 571 2,235 668 Restricted stock units 379 — 479 — Warrants — 71 — 71

Loan Payable and Warrant to P23

Loan Payable and Warrant to Purchase Common Stock (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Summary of Significant Assumptions Used in Warrant Fair Value Measurements	The Company used the following weighted-average assumptions: Expected volatility 73.71 % Expected term (in years) 5 Risk-free interest rate 1.75 % Expected dividend yield — %

Nature of Business - Additional

Nature of Business - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2017	Jun. 08, 2017	Mar. 03, 2017	Dec. 31, 2016
Subsidiary, Sale of Stock [Line Items]
Cash and cash equivalents and investments	$ 207,100,000
Period of sufficiency of cash resources to fund operating plan	12 months
Accumulated deficit	$ (70,177,000)			$ (171,882,000)
Assets for synthesis and research and development for treating Cystic Fibrosis | Disposed of by sale, not discontinued operations
Subsidiary, Sale of Stock [Line Items]
Consideration transferred			$ 250,000,000
Cash consideration			160,000,000
Loan Agreement | Secured Term Loan Facility | Line of Credit
Subsidiary, Sale of Stock [Line Items]
Secured term loan facility amount		$ 30,000,000
Indemnification agreement | Assets for synthesis and research and development for treating Cystic Fibrosis | Disposed of by sale, not discontinued operations
Subsidiary, Sale of Stock [Line Items]
Guarantor maximum liability			$ 16,000,000

Basis of Presentation and Sig25

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2017segment
Accounting Policies [Abstract]
Number of segments	1

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Recognized at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets at fair value	$ 198,352	$ 82,888
Fair value measurements | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets at fair value	155,281	60,836
Fair value measurements | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets at fair value	43,071	22,052
Fair value measurements | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets at fair value	0	0
Shorter maturity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	32,119	40,555
Shorter maturity | Fair value measurements | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	18,361	26,257
Shorter maturity | Fair value measurements | Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	18,361	26,257
Shorter maturity | Fair value measurements | Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	0	0
Shorter maturity | Fair value measurements | Money market funds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	0	0
Shorter maturity | Fair value measurements | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	4,998	1,001
Shorter maturity | Fair value measurements | U.S. Treasury obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	4,998	0
Shorter maturity | Fair value measurements | U.S. Treasury obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	0	1,001
Shorter maturity | Fair value measurements | U.S. Treasury obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, cash equivalents	0	0
Longer maturity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	174,993	55,630
Longer maturity | Fair value measurements | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	58,771	15,537
Longer maturity | Fair value measurements | U.S. Treasury obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	58,771	10,034
Longer maturity | Fair value measurements | U.S. Treasury obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	0	5,503
Longer maturity | Fair value measurements | U.S. Treasury obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	0	0
Longer maturity | Fair value measurements | Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	116,222	40,093
Longer maturity | Fair value measurements | Government agency securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	73,151	24,545
Longer maturity | Fair value measurements | Government agency securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	43,071	15,548
Longer maturity | Fair value measurements | Government agency securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, investments available-for-sale securities	$ 0	$ 0

Cash, Cash Equivalents and In27

Cash, Cash Equivalents and Investments (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, cash and cash equivalents	$ 32,119	$ 40,555	$ 29,803	$ 92,510
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, investments available for sale	32,119	40,555
Unrealized gains	0	0
Unrealized losses	0	0
Fair value, available-for-sale securities	32,119	40,555
Investments, available for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, investments available for sale	175,060	55,637
Unrealized gains	2	5
Unrealized losses	(69)	(12)
Fair value, available-for-sale securities	174,993	55,630
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, cash and cash equivalents	8,760	13,297
Fair value, cash and cash equivalent	8,760	13,297
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, cash and cash equivalents	18,361	26,257
Fair value, cash and cash equivalent	$ 18,361	$ 26,257
U.S. Treasury obligations | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Average maturity (in years)	19 days	31 days
Amortized cost, investments available for sale	$ 4,998	$ 1,001
Unrealized gains	0	0
Unrealized losses	0	0
Fair value, available-for-sale securities	$ 4,998	$ 1,001
U.S. Treasury obligations | Investments, available for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Average maturity (in years)	188 days	125 days
Amortized cost, investments available for sale	$ 58,794	$ 15,534
Unrealized gains	0	4
Unrealized losses	(23)	(1)
Fair value, available-for-sale securities	$ 58,771	$ 15,537
Government agency securities | Investments, available for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Average maturity (in years)	256 days	140 days
Amortized cost, investments available for sale	$ 116,266	$ 40,103
Unrealized gains	2	1
Unrealized losses	(46)	(11)
Fair value, available-for-sale securities	$ 116,222	$ 40,093

Cash, Cash Equivalents and In28

Cash, Cash Equivalents and Investments - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Realized gains or losses on sales of investments	$ 0	$ 0
Other than temporary impairment losses, investments	$ 0	$ 0

Accrued Expenses and Other Li29

Accrued Expenses and Other Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued professional fees and other	$ 507	$ 487
Employee compensation and benefits	1,810	2,010
Research and development expenses	615	930
Deferred lease incentive, current portion	331	324
Deferred rent, current portion	139	102
Accrued expenses and other liabilities	$ 3,402	$ 3,853

Asset Purchase Agreement (Detai

Asset Purchase Agreement (Details) - USD ($)	Mar. 03, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue recognized		$ 143,844,000	$ 26,000	$ 143,879,000	$ 153,000
Disposed of by sale, not discontinued operations | Assets for synthesis and research and development for treating Cystic Fibrosis
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration	$ 160,000,000
Revenue recognized				143,800,000
Remaining deferred revenue		$ 300,000		$ 300,000
Contingent consideration asset, After achievement of milestone events | Disposed of by sale, not discontinued operations | Assets for synthesis and research and development for treating Cystic Fibrosis
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent consideration receivable	90,000,000
Contingent consideration asset, Upon receipt of FDA marketing approval | Disposed of by sale, not discontinued operations | Assets for synthesis and research and development for treating Cystic Fibrosis
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent consideration receivable	50,000,000
Contingent consideration asset, Upon completion of pricing and reimbursement agreement | Disposed of by sale, not discontinued operations | Assets for synthesis and research and development for treating Cystic Fibrosis
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent consideration receivable	40,000,000
Indemnification agreement | Disposed of by sale, not discontinued operations | Assets for synthesis and research and development for treating Cystic Fibrosis
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Guarantor maximum liability	$ 16,000,000
Guarantor obligations term	18 months
Collaborative arrangement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Allocable arrangement consideration	$ 144,100,000
Collaborative arrangement | Transfer of IP Deliverable
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Allocable arrangement consideration	143,700,000
Collaborative arrangement | Transition Services Deliverable
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Allocable arrangement consideration	$ 400,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income tax expense	$ 2,177	$ 0	$ 2,177	$ 0

Collaborations - Celgene - Addi

Collaborations - Celgene - Additional Information (Detail)	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2013USD ($)licenseoption	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)	Oct. 30, 2015USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue, current portion		$ 1,388,000		$ 1,388,000		$ 1,172,000
License, research and development revenue		17,000	$ 26,000	52,000	$ 153,000
Deferred revenue, noncurrent		8,921,000		8,921,000		$ 8,878,000
Celgene
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of additional license program | license	2
Deferred revenue, current portion		1,100,000		1,100,000
Percentage of royalty on net sales required to pay under the agreement	20.00%
Deferred revenue		7,200,000		7,200,000
Deferred revenue, noncurrent		6,100,000		6,100,000
Celgene | License exercise fee
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of options for providing license program | option	1
Celgene | If Celgene exercises its option with respect to the option program
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue, current portion	$ 10,000,000
Celgene | If Celgene exercises its option with respect to the option program | Development milestone | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	23,000,000
Celgene | If Celgene exercises its option with respect to the option program | Regulatory milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	247,500,000
Celgene | If Celgene exercises its rights with respect to either of the two additional license programs | Development milestone | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	23,000,000
Celgene | If Celgene exercises its rights with respect to either of the two additional license programs | Regulatory milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	247,500,000
Celgene | If Celgene exercises its rights with respect to either of the two additional license programs | Sales-based milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	$ 100,000,000
Celgene | If Celgene exercises its rights with respect to either of the two additional license programs | License exercise fee
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of options for providing license program | option	2
Deferred revenue, current portion	$ 30,000,000
Celgene | One of the other additional license programs | Sales-based milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	50,000,000
Celgene | Research and development services deliverable
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, research and development revenue		$ 8,000	$ 9,000	$ 20,000	$ 68,000
Celgene | CTP-730 Program | Non-refundable upfront payment arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue, payment received	35,000,000
Celgene | CTP-730 Program | Development milestone
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable							$ 8,000,000
Celgene | CTP-730 Program | Regulatory milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	247,500,000
Celgene | CTP-730 Program | Sales-based milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	50,000,000
Celgene | CTP-730 Program | If Celgene exercises its option with respect to the option program | Development milestone
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	15,000,000
Celgene | Product collaborative arrangement | CTP-730 Program | Development milestone | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	$ 15,000,000

Collaborations - Jazz Pharmaceu

Collaborations - Jazz Pharmaceuticals - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2013	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, research and development revenue		$ 17,000	$ 26,000	$ 52,000	$ 153,000
Jazz Pharmaceuticals
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales required to pay under the agreement	20.00%
Jazz Pharmaceuticals | Non-refundable upfront payment arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue, payment received	$ 4,000,000
Jazz Pharmaceuticals | Regulatory milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	35,000,000
Jazz Pharmaceuticals | Sales-based milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	70,000,000
Jazz Pharmaceuticals | Development support services
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License, research and development revenue		$ 9,000	$ 18,000	$ 31,000	$ 86,000
Jazz Pharmaceuticals | JZP 386
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	4,000,000
Jazz Pharmaceuticals | Co-promotion collaborative arrangement | Development milestone | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	$ 8,000,000

Collaborations - Avanir - Addit

Collaborations - Avanir - Additional Information (Detail) - Avanir Pharmaceuticals - USD ($)	1 Months Ended
	Feb. 29, 2012	Sep. 30, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable		$ 6,000,000
Non-refundable upfront payment arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	$ 2,000,000
Regulatory and commercial launch milestone | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	37,000,000
Development milestone | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	21,500,000
Sales-based milestones | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	$ 125,000,000
Product collaborative arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales required to pay under the agreement	20.00%
Product collaborative arrangement | Licensed product
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	$ 43,000,000
Co-promotion collaborative arrangement | AVP-786 Program | Development milestone
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	3,000,000
US Food and Drug Administration | Product collaborative arrangement | AVP-786 Program | Development milestone
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	5,000,000
Ministry of Health, Labour and Welfare (MHLW) | Product collaborative arrangement | AVP-786 Program | Development milestone
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible payments receivable	$ 1,500,000

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Jul. 06, 2017	Jan. 01, 2017	Sep. 30, 2017	Sep. 30, 2017
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated forfeiture rate				7.00%
Total unrecognized compensation cost related to unvested options			$ 11.4	$ 11.4
Total unrecognized compensation cost, weighted-average recognition period				2 years 6 months
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost, weighted-average recognition period				1 year 2 months 12 days
Number of RSU shares, granted (in shares)	500,000			520,500
Number of RSU shares, vested (in shares)				0
Weighted average exercise price reduction, granted (in dollars per share)				$ 0.001
Weighted average grant date fair value, granted (in dollars per share)			$ 13.87	$ 13.87
Total unrecognized compensation cost related to restricted stock units			$ 4.9	$ 4.9
Restricted stock units | Tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	50.00%
Restricted stock units | Tranche two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	50.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Awards expiration period				10 years
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares issued under the plan (in shares)		892,679
Common stock available for future award grant (in shares)			1,191,572	1,191,572

Stock Based Compensation - Stoc

Stock Based Compensation - Stock-Based Compensation Expense Related to All Stock Based Awards Recognized in Statements of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,497	$ 1,262	$ 5,713	$ 3,831
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,105	532	2,507	1,638
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,392	$ 730	$ 3,206	$ 2,193

Stock Based Compensation - Esti

Stock Based Compensation - Estimated Weighted-Average Assumptions of Options Granted (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected volatility	77.34%	78.07%	78.15%	78.29%
Expected term	6 years	6 years	6 years	6 years
Risk-free interest rate	2.04%	1.28%	2.07%	1.35%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average grant date fair value of options granted, per option (dollars per share)	$ 9.51	$ 6.75	$ 7.67	$ 10.47
Aggregate grant date fair value of options vested during the period	$ 1,634	$ 1,143	$ 4,601	$ 3,527
Total cash received from exercises of stock options	939	54	2,396	293
Total intrinsic value of stock options exercised	$ 1,052	$ 101	$ 4,361	$ 729

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)$ / sharesshares
Number of Option Shares
Number of options, Outstanding beginning balance (in shares) | shares	2,953,961
Number of options, Granted (in shares) | shares	1,065,500
Number of options, Exercised (in shares) | shares	(436,531)
Number of options, Forfeited or expired (in shares) | shares	(183,442)
Number of options, Outstanding ending balance (in shares) | shares	3,399,488
Number of options, Exercisable (in shares) | shares	1,804,330
Number of options, Vested and expected to vest (in shares) | shares	3,260,214
Weighted Average Exercise Price per Share
Weighted average exercise price per share, Outstanding at beginning of year (in dollars per share) | $ / shares	$ 10.49
Weighted average exercise price per share, Granted (in dollars per share) | $ / shares	11.25
Weighted average exercise price per share, Exercised (in dollars per share) | $ / shares	5.57
Weighted average exercise price per share, Forfeited or expired (in dollars per share) | $ / shares	12.39
Weighted average exercise price per share, Outstanding ending balance (in dollars per share) | $ / shares	11.25
Weighted average exercise price per share, Exercisable (in dollars per share) | $ / shares	10.03
Weighted average exercise price per share, Vested and expected to vest (in dollars per share) | $ / shares	$ 11.20
Weighted Average Remaining Contractual Term (In years)
Weighted average remaining contractual term, Outstanding	6 years 6 months 25 days
Weighted average remaining contractual term, Exercisable	5 years 5 months 9 days
Weighted average remaining contractual term, Vested and expected to vest	6 years 6 months 3 days
Aggregate Intrinsic Value
Aggregate intrinsic value, Outstanding | $	$ 13,434
Aggregate intrinsic value, Exercisable | $	9,170
Aggregate intrinsic value, Vested and expected to vest | $	$ 13,042

Stock-Based Compensation - Su40

Stock-Based Compensation - Summary of RSU Activity (Details) - Restricted stock units - $ / shares	Jul. 06, 2017	Sep. 30, 2017	Sep. 30, 2017
Number of RSU Shares
Number of RSU shares, Outstanding beginning balance (in shares)			0
Number of RSU shares, Granted (in shares)	500,000		520,500
Number of RSU shares, Released (in shares)			0
Number of RSU shares, Forfeited (in shares)			0
Number of RSU shares, Outstanding ending balance (in shares)		520,500	520,500
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, Outstanding at beginning of year (in dollars per share)			$ 0
Weighted average grant date fair value, Granted (in dollars per share)		$ 13.87	13.87
Weighted average grant date fair value, Released (in dollars per share)			0
Weighted average grant date fair value, Forfeited (in dollars per share)			0
Weighted average grant date fair value, Outstanding at ending of year (in dollars per share)		$ 13.87	$ 13.87

Earnings (Loss) Per Share - Com

Earnings (Loss) Per Share - Computation of Basic and Diluted Earnings (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income (loss)	$ 128,065	$ (11,356)	$ 101,705	$ (38,677)
Income attributable to participating securities - basic	741	0	433	0
Income (loss) attributable to common stockholders - basic	127,324	(11,356)	101,272	(38,677)
Income attributable to participating securities - diluted	718	0	421	0
Income (loss) attributable to common stockholders - diluted	$ 127,347	$ (11,356)	$ 101,284	$ (38,677)
Denominator:
Weighted average shares outstanding - basic (in shares)	22,694	22,229	22,551	22,215
Net income (loss) per share applicable to common stockholders - basic (in dollars per share)	$ 5.61	$ (0.51)	$ 4.49	$ (1.74)
Dilutive impact from:
Weighted average shares outstanding - diluted (in shares)	23,421	22,229	23,195	22,215
Net income (loss) per share applicable to common stockholders - diluted (in dollars per share)	$ 5.44	$ (0.51)	$ 4.37	$ (1.74)
Stock options
Anti-dilutive potential common stock equivalents excluded from the calculation of net income (loss) per share:
Anti-dilutive stock options, restricted stock units, and warrants (in shares)	2,172	571	2,235	668
Restricted stock units
Anti-dilutive potential common stock equivalents excluded from the calculation of net income (loss) per share:
Anti-dilutive stock options, restricted stock units, and warrants (in shares)	379	0	479	0
Warrants
Anti-dilutive potential common stock equivalents excluded from the calculation of net income (loss) per share:
Anti-dilutive stock options, restricted stock units, and warrants (in shares)	0	71	0	71
Stock options
Dilutive impact from:
Dilutive impact from stock options, restricted stock units, and warrants (in shares)	585	0	602	0
Restricted stock units
Dilutive impact from:
Dilutive impact from stock options, restricted stock units, and warrants (in shares)	142	0	42	0

Loan Payable and Warrant to P42

Loan Payable and Warrant to Purchase Common Stock - Additional Information (Details) - USD ($)	Sep. 07, 2017	Jun. 08, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Debt Instrument [Line Items]
Repayment of loan					$ 30,745,000	$ 0
Loss on extinguishment of debt			$ 1,432,000	$ 0	$ 1,432,000	$ 0
Loan Agreement
Debt Instrument [Line Items]
Amount of warrants issued and exercisable (in shares)		61,273
Warrant exercise price (in dollars per share)		$ 12.24
Warrant expiration term		5 years
Warrants total relative fair value		$ 500,000
Line of Credit | Secured Term Loan Facility | Loan Agreement
Debt Instrument [Line Items]
Secured term loan facility amount		30,000,000
Loan issuance costs incurred		$ 300,000
Secured term loan variable rate		8.55%
Interest rate during period		8.55%
Repayment of loan	$ 30,800,000
Loss on extinguishment of debt			$ 1,400,000
End of term charge	$ 700,000
Original end of term charge		$ 1,500,000
Line of Credit | Secured Term Loan Facility | Loan Agreement | Minimum
Debt Instrument [Line Items]
Prepayment charge waived term		90 days
Line of Credit | Secured Term Loan Facility | Loan Agreement | Maximum
Debt Instrument [Line Items]
Prepayment charge waived term		6 months
Line of Credit | Secured Term Loan Facility | Loan Agreement | Prime rate
Debt Instrument [Line Items]
Basis spread on variable rate		4.50%

Loan Payable and Warrant to P43

Loan Payable and Warrant to Purchase Common Stock - Summary of Significant Assumptions Used in Warrant Fair Value Measurements (Details) - Warrants	Jun. 08, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected volatility	73.71%
Expected term (in years)	5 years
Risk-free interest rate	1.75%
Expected dividend yield	0.00%