Receptos (RCPT) 10-Q 31 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 15, 2013
Document and Entity Information
Entity Registrant Name	Receptos, Inc.
Entity Central Index Key	1463729
Document Type	10-Q
Document Period End Date	30-Sep-13
Amendment Flag	FALSE
Current Fiscal Year End Date	-19
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		18,337,797
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$80,781	$5,427
Prepaid expenses and other current assets	665	786
Total current assets	81,446	6,213
Property and equipment, net	358	549
Other assets, net	297	141
Total assets	82,101	6,903
Current liabilities:
Accounts payable	1,202	1,019
Accrued compensation and benefits	1,318	1,028
Accrued expenses	8,262	1,682
Repurchase liability for unvested restricted stock awards	132	188
Current portion of term loan	441
Current portion of deferred revenue	1,473	2,225
Total current liabilities	12,828	6,142
Term loan	4,428
Deferred revenue, less current portion		700
Deferred rent	141	228
Total liabilities	17,397	7,070
Stockholders' (deficit) equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized as of September 30, 2013; no shares issued or outstanding
Common stock, $0.001 par value; 113,532,927 and 200,000,000 shares authorized at December 31, 2012 and September 30, 2013, respectively; 2,417,024 and 18,337,797 shares issued and outstanding at December 31, 2012 and September 30, 2013, respectively	18	2
Additional paid-in capital	145,351	7,604
Accumulated deficit	-80,665	-47,589
Total stockholders' (deficit) equity	64,704	-39,983
Total liabilities, convertible preferred stock and stockholders' (deficit) equity	82,101	6,903
Series A Convertible Preferred Stock
Temporary equity
Convertible Preferred Stock		27,260
Series B Convertible Preferred Stock
Temporary equity
Convertible Preferred Stock		$12,556

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Preferred stock, par value (in dollars per share)	$0.00
Preferred stock, shares authorized	10,000,000
Preferred stock, shares issued	0
Preferred stock, shares outstanding	0
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	200,000,000	113,532,927
Common stock, shares issued	18,337,797	2,417,024
Common stock, shares outstanding	18,337,797	2,417,024
Series A Convertible Preferred Stock
Preferred stock, par value (in dollars per share)	$0.00	$0.00
Preferred stock, shares authorized	0	39,375,697
Preferred stock, shares issued	0	39,375,697
Preferred stock, shares outstanding	0	39,375,697
Series B Convertible Preferred Stock
Preferred stock, par value (in dollars per share)	$0.00	$0.00
Preferred stock, shares authorized	0	48,543,700
Preferred stock, shares issued	0	12,357,561
Preferred stock, shares outstanding	0	12,357,561

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Collaborative revenue	$1,142	$1,794	$3,868	$4,809
Operating expenses:
Research and development	13,500	6,757	30,961	15,434
General and administrative	3,050	1,041	5,701	2,627
Total operating expenses	16,550	7,798	36,662	18,061
Loss from operations	-15,408	-6,004	-32,794	-13,252
Other income (expense):
Interest income	2	4	8	16
Other expense	-159	-3	-290	-18
Net loss and comprehensive loss	-15,565	-6,003	-33,076	-13,254
Preferred stock deemed dividend			-2,056
Net loss attributable to common stockholders	($15,565)	($6,003)	($35,132)	($13,254)
Net loss per common share, basic and diluted (in dollars per share)	($0.88)	($4.44)	($3.54)	($10.71)
Weighted-average shares used to compute net loss per common share, basic and diluted (in shares)	17,715	1,351	9,928	1,237

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net loss	($33,076)	($13,254)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,666	146
Depreciation and amortization	261	518
Deferred rent	-87	52
Other	95
Changes in operating assets and liabilities:
Prepaid expenses and other assets	-127	194
Accounts payable and accrued expenses	6,838	1,776
Accrued compensation and benefits	290	-95
Deferred revenue	-1,452	-1,208
Net cash used in operating activities	-25,592	-11,871
Cash flows from investing activities
Purchases of property and equipment	-70	-211
Net cash used in investing activities	-70	-211
Cash flows from financing activities
Net proceeds from issuance of convertible preferred stock	21,192	12,556
Net proceeds from initial public offering of common stock	75,009
Proceeds from exercise of common stock options and common stock warrants	25	51
Proceeds from borrowings under term loan, net of issuance costs	4,790
Proceeds from early exercise of stock options		138
Net cash provided by financing activities	101,016	12,745
Increase in cash and cash equivalents	75,354	663
Cash and cash equivalents at beginning of the period	5,427	11,336
Cash and cash equivalents at end of the period	80,781	11,999
Supplemental cash flow information
Conversion of Series A and B Preferred Stock to common stock	63,064
Release of repurchase liability for stock options and restricted stock shares	56	34
Non-cash financing activity
Preferred stock deemed dividend	$2,056

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Organization and Basis of Presentation
Organization and Basis of Presentation	1.              Organization and Basis of Presentation
	Description of Business
	Receptos, Inc. is a biopharmaceutical company focused on discovering, developing and commercializing innovative therapeutics in immune disease for specialty markets including for Relapsing Multiple Sclerosis (RMS), Inflammatory Bowel Disease (IBD) and Eosinophilic Esophagitis (EoE). The Company was incorporated in the state of Delaware on September 26, 2008 under the name Receptor Pharmaceuticals, Inc, and commenced significant operations in 2009. On May 11, 2009, (i) Receptor Pharmaceuticals, Inc. filed an Amended and Restated Certificate of Incorporation which, among other things, changed its name to Receptos, Inc., and (ii) pursuant to an Agreement and Plan of Merger by and among Receptos, Inc., Apoptos Acquisition Corporation (a wholly owned subsidiary of Receptos, Inc.) and Apoptos, Inc., Apoptos Acquisition Corporation merged with and into Apoptos, Inc. with Apoptos, Inc. continuing as the surviving corporation and becoming a wholly owned subsidiary of Receptos, Inc. As used in this report, unless the context suggests otherwise, “the Company” and “Receptos” mean Receptos, Inc.
	The condensed consolidated financial statements include the accounts of Receptos, Inc. and its wholly-owned subsidiary, Apoptos, Inc. (Apoptos), which is currently inactive. All intercompany balances and transactions have been eliminated in consolidation.
	Basis of Presentation
	The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the Securities and Exchange Commission (“SEC”) related to a quarterly report on Form 10-Q. Certain information and note disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted pursuant to those rules and regulations. The unaudited interim condensed consolidated financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. In the opinion of management, all such adjustments are of a normal and recurring nature. The operating results presented in these unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods.  These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto for the year ended December 31, 2012 included in our final prospectus filed with the SEC on May 9, 2013 relating to our Registration Statement on Form S-1 (File No. 333-187737) for our initial public offering (IPO).
	Liquidity
	The Company has incurred losses since inception and negative cash flows from operating activities and, as of September 30, 2013, the Company had an accumulated deficit of $80.7 million. The Company anticipates that it will continue to incur net losses into the foreseeable future as it: (i) continues the development and commercialization of its lead drug candidate RPC1063; (ii) works to develop additional drug candidates through research and development programs; and (iii) expands its corporate infrastructure. The Company plans to continue to fund its losses from operations and capital funding needs through cash on hand, as well as future debt and equity financing and potential collaboration arrangements. If the Company is not able to secure adequate additional funding, it may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, and/or suspend or curtail planned programs. Any of these actions could materially harm the Company’s business, results of operations and future prospects.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2.              Summary of Significant Accounting Policies
	Use of Estimates
	The preparation of the Company’s condensed consolidated financial statements and accompanying notes in conformity with GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities.  The most significant estimates in the Company’s condensed consolidated financial statements relate to clinical trial accruals, revenue recognition and stock-based compensation. Although these estimates and assumptions are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately differ materially from these estimates and assumptions.
	Segment Reporting
	Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment operating primarily in the US.
	Cash and Cash Equivalents
	The Company classifies time deposits and other investments that are highly liquid and have maturities of 90 days or less at the date of purchase as cash equivalents. The carrying amounts approximate fair value due to the short maturities of these instruments. Cash and cash equivalents include cash in checking and money market accounts.
	Fair Value of Financial Instruments
	The carrying amounts of all cash equivalents, accounts payable and accrued liabilities are reasonable estimates of their fair value because of the short nature of these items.
	The valuation of assets and liabilities are subject to fair value measurements using a three tiered approach and fair value measurement is classified and disclosed by the Company in one of the following three categories:
	Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
	Level 2: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability;
	Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
	Cash and cash equivalents are measured at fair value on a recurring basis. As of December 31, 2012 and September 30, 2013, cash equivalents are classified within the Level 1 designation as noted above. As of December 31, 2012 and September 30, 2013, the carrying amount of cash equivalents was $5.3 million and $77.0 million, respectively, which approximates fair value and was determined based upon Level 1 inputs. Cash equivalents consisted of funds held in money market accounts. As of December 31, 2012 and September 30, 2013, the Company does not hold any Level 2 or Level 3 financial instruments.
	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial position of the depository institutions in which those deposits are held. The Company maintains cash equivalents with two financial institutions. The Company invests excess cash in money market accounts. Additionally, the Company has established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.
	Property and Equipment
	The Company records its property and equipment at cost and computes depreciation using the straight-line method over the estimated useful lives of the assets (generally three years). The Company amortizes leasehold improvements over the lease term or the useful life of the improvement, whichever is shorter (including any renewal periods that are deemed to be reasonably assured). The Company expenses repair and maintenance costs that do not improve service potential or extend economic life as incurred.
	Impairment of Long-Lived Assets
	The Company reviews property and equipment for impairment on an annual basis and whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. An impairment loss would be recognized when estimated future undiscounted cash flows relating to the asset are less than its carrying amount. An impairment loss is measured as the amount by which the carrying amount of an asset exceeds its fair value. While the Company’s current and historical operating losses and negative cash flows are possible indicators of impairment, management believes that the future cash flows to be generated by these assets support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses through September 30, 2013.
	IncomeTaxes
	The Company follows the accounting guidance on accounting for uncertainty in income taxes. The guidance prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position.
	The Company uses the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made.
	Revenue Recognition
	The Company enters into arrangements with pharmaceutical and biotechnology partners that may involve multiple deliverables. The Company’s arrangements may contain upfront payments, license fees for research and development arrangements, research and development funding and milestone payments under collaborative agreements. Each deliverable in the arrangement is evaluated to determine whether it meets the criteria to be accounted for as a separate unit of accounting or whether it should be combined with other deliverables. Revenue is recognized separately for each unit of accounting when all four of the following criteria are met: (i) persuasive evidence that an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the selling price is fixed or determinable; and (iv) collectability is reasonably assured.
	Upfront Fees. When management determines the Company has a single unit of accounting under its collaborative arrangements, upfront fees received for collaborative agreements are recognized ratably over the expected performance period under each respective arrangement. The Company’s collaborations to date have had stated periods of performance; however, the agreement with Ono Pharmaceutical Co., Ltd., or Ono, contains an option whereby Ono may choose to extend the development period. As a result, management makes its best estimate of the period over which the Company expects to fulfill its performance obligations under that agreement. Any amounts received under the agreements in advance of performance, if deemed substantive, are recorded as deferred revenue and recognized as revenue as the Company completes its performance obligations.
	Milestones. The Company evaluates all milestones at the beginning of the agreement to determine if they meet the definition of a substantive milestone. Revenue is recognized from milestone payments when earned, provided that (i) the milestone event is substantive in that it can only be achieved based in whole or in part on either the Company’s performance or on the occurrence of a specific outcome resulting from the Company’s performance and its achievability was not reasonably assured at the inception of the agreement, (ii) the Company does not have ongoing performance obligations related to the achievement of the milestone and (iii) it would result in the receipt of additional payments. A milestone payment is considered substantive if all of the following conditions are met: (i) the milestone payment is non-refundable; (ii) achievement of the milestone was not reasonably assured at the inception of the arrangement; (iii) substantive effort is involved to achieve the milestone; and (iv) the amount of the milestone payments appears reasonable in relation to the effort expended, the other milestones in the arrangement and the related risk associated with the achievement of the milestone.
	The Company’s collaboration arrangements provide for payments upon the achievement of research milestones, such as providing structure solutions with candidate compounds for certain targets. Given the challenges inherent in determining high resolution structure solutions for G protein-coupled receptor (GPCR) targets, there was substantial uncertainty whether any such milestones would be achieved at the time the Company entered into these collaboration arrangements. In addition, the Company evaluated whether the research milestones met the remaining criteria to be considered substantive. As a result of its analysis, management considers most of the Company’s research milestones to be substantive and, accordingly, it expects to recognize as revenue future payments received from such milestones as each milestone is achieved. For those milestones that in management’s judgment did not meet the additional criteria to be considered substantive, these payments are deferred upon achievement and recognized ratably in the condensed consolidated statements of operations and comprehensive loss over the remaining estimated period of its performance.
	Deferred Revenue. Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying condensed consolidated balance sheets. Amounts not expected to be recognized within the next 12 months are classified as non-current deferred revenue.
	Research and Development
	Research and development costs are expensed as incurred.
	Patent Expenses
	Costs related to filing and pursuing patent applications are recorded as general and administrative expense since recoverability of such expenditures is uncertain.
	Stock-Based Compensation
	The Company accounts for stock-based compensation expense related to stock options granted to employees and members of its board of directors by estimating the fair value of each stock option on the date of grant using the Black-Scholes options-pricing model net of estimated forfeitures. For awards subject to time-based vesting conditions, stock-based compensation expense is recognized using the straight-line method. In accordance with the authoritative accounting literature, options subject to both performance and time-based vesting conditions are expensed using an accelerated multiple-option approach. Under the accelerated multiple-option approach (also known as the graded-vesting method), compensation expense is recognized over the requisite service period for each separately vesting tranche of the award as though the award was in substance multiple awards, resulting in accelerated expense recognition during the earlier vesting periods.
	The Company accounts for stock options granted to non-employees using the fair value approach. Stock options granted to non-employees are subject to periodic revaluation over their vesting terms.
	Comprehensive Loss
	Comprehensive loss is defined as the change in equity during a period from transactions and other events and/or circumstances from non-owner sources. Comprehensive loss is equal to net loss for all periods presented.
	Net Loss per Share
	Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Excluded from the weighted-average number of shares outstanding are shares which have been issued upon the early exercise of stock options and are subject to future vesting and unvested restricted stock totaling 1.0 million and 0.6 million shares as of September 30, 2012 and 2013, respectively. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of convertible preferred stock, stock options and warrants.  Basic and diluted net loss per share are equivalent because the Company has incurred a net loss in all periods presented causing any potentially dilutive securities to be anti-dilutive. The following table summarizes the weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share (in thousands):
		Three months ended		Nine months ended
		September 30,		September 30,
		2012	2013	2012	2013
	Convertible preferred stock	6,898	—	6,706	4,061
	Common stock equivalents:
	Options to purchase common stock	154	1,107	224	578
	Warrants to purchase common stock	343	—	358	—
	Total	7,395	1,107	7,888	4,639
	Recent Accounting Pronouncements
	In February 2013, the Financial Accounting Standards Board issued an accounting standard update to require reclassification adjustments from other comprehensive income to be presented either in the financial statements or in the notes to the financial statements. This accounting standard became effective for the Company beginning in the first quarter of fiscal 2013, and its adoption did not have any impact on the Company’s consolidated financial statements.

Balance_Sheet_Details

Balance Sheet Details	9 Months Ended
	Sep. 30, 2013
Balance Sheet Details
Balance Sheet Details	3.              Balance Sheet Details
	Prepaid Expenses and Other Current Assets
	The following table summarizes major classes of prepaid expenses and other current assets (in thousands):
		December 31,			September 30,
		2012			2013
	Prepaid contract research	$	435		$	—
	Prepaid maintenance agreements	92			98
	Prepaid rent	69			79
	Prepaid insurance	62			343
	Prepaid other	128			145
	Total	$	786		$	665
	Property and Equipment
	The following table summarizes major classes of property and equipment (in thousands):
		Useful		December 31			September 30,
		life		2012			2013
	Laboratory equipment	3 years		$	2,940		$	3,004
	Computer equipment and software	3 years		226			232
	Leasehold improvements	7 years		854			854
				4,020			4,090
	Less accumulated depreciation and amortization			(3,471		)	(3,732		)
	Property and equipment, net			$	549		$	358
	Depreciation and amortization expense was $0.1 million and $0.5 million for the three and nine months ended September 30, 2012, respectively, and $0.1 million and $0.3 million for the three and nine months ended September 30, 2013, respectively.
	Accrued Expenses
	The following table summarizes major classes of accrued expenses (in thousands):
		December 31			September 30,
		2012			2013
	Clinical trial accrual	$	1,289		$	5,870
	Accrued royalty payable	176			—
	Other accrued liabilities	217			2,392
	Total	$	1,682		$	8,262

Collaborative_Arrangements

Collaborative Arrangements	9 Months Ended
	Sep. 30, 2013
Collaborative Arrangements
Collaborative Arrangements	4.              Collaborative Arrangements
	The Company has entered into various license agreements and collaborative research and development arrangements with pharmaceutical and biotechnology companies. Under these arrangements, the Company is entitled to receive license fees, upfront payments, milestone payments when and if certain research milestones are achieved, development milestones in one instance based solely upon the Company’s partner’s performance and/or reimbursement for research and development activities. All of the Company’s collaboration arrangements are generally cancelable by its partners without significant financial penalty to the partner. The Company’s costs of performing these services are included in research and development expense.
	The Company recognized collaborative revenue under these arrangements as follows (in thousands):
		Three months ended				Nine months ended
		September 30,				September 30,
	Partner	2012		2013		2012		2013
	Ono Pharmaceutical Co., Ltd.	$	1,174	$	1,142	$	2,850	$	3,868
	Eli Lilly and Company	620		—		1,880		—
	Other	—		—		79		—
	Total	$	1,794	$	1,142	$	4,809	$	3,868
	Collaboration with Ono Pharmaceutical Co., Ltd. In December 2011, the Company entered into a 30-month co-exclusive Collaboration Agreement, or the Ono Agreement, with Ono to utilize the Company’s proprietary GPCR structure determination technologies for the identification of a high resolution novel protein crystal structure of an Ono proprietary GPCR drug discovery target. The Company is responsible for successful completion of protein expression, crystallization studies and structure determination with respect to the GPCR drug discovery target for Ono and Ono is providing research funding through the term of the agreement. Ono will receive an exclusive license, even as to the Company, with the right to sublicense, under all of the Company’s interests in certain intellectual property rights developed as part of the collaboration. Upon payment of all pre-defined research milestones in the Ono Agreement, the Company’s interests in such intellectual property rights will thereafter be assigned to Ono. Ono will also receive a non-exclusive license, with the right to sublicense, under certain other intellectual property rights. Upon payment of the first development milestone payment to the Company, such license from the Company to Ono shall become perpetual.
	In December 2011, Ono paid the Company an upfront, non-refundable fee of $2.5 million as consideration for technology access over the term of the agreement. It was determined that there was one unit of accounting under the Ono Agreement with respect to this upfront fee (which is a collaborative arrangement to provide research and development services). As such, this fee is being recognized as collaborative revenue on a straight-line basis over the contract term.
	The Ono Agreement provides for payments to the Company upon achievement of certain milestone events. The Company concluded that certain of these milestone payments did not meet the definition of a substantive milestone, inasmuch as achievability was reasonably assured at the inception of the Ono Agreement. Revenue totaling $1.5 million arising from milestone events which did not meet the criteria of substantive milestones has been deferred and is being amortized over the remaining term of the Ono Agreement. Management determined that the criteria necessary for concluding all of the remaining milestones associated with the Ono Agreement to be substantive were met at the inception of the contract, and as such, the Company is recognizing revenue related to these remaining research milestones when it is earned. Operating results for the nine months ended September 30, 2013 include collaborative revenues of $0.3 million associated with achievement of research milestones that management has determined satisfy the criteria for treatment as substantive milestones. There was no similar substantive milestone revenue for either of the comparable prior year periods. Future potential substantive milestones based upon the Company’s research efforts could total up to $2.0 million, while future potential development milestones based on Ono’s efforts could total up to $15.0 million.
	The Ono Agreement also calls for Ono to pay the Company for ongoing research and development support. The quarterly research and development support payments are being recognized in the condensed consolidated statements of operations and comprehensive loss as collaborative revenue as the services are provided. Such revenues totaled $0.8 million and $1.7 million for the three and nine months ended September 30, 2012, respectively, and $0.7 million and $2.4 million for the three and nine months ended September 30, 2013, respectively.
	The Company’s condensed consolidated balance sheet as of September 30, 2013 includes deferred revenues of $1.5 million associated with the Ono Agreement.
	In addition to the above, the Ono Agreement also provides for contingent payments to the Company for development milestones based solely upon Ono’s performance. As the Ono Agreement does not require the Company to provide any future support in order to receive these milestone payments, revenue from these development milestones will be recognized as it is earned provided that collection is reasonably assured.
	Eli Lilly and Company. In December 2010, the Company entered into a two-year co-exclusive Collaborative Agreement with Eli Lilly and Company, or Lilly, to utilize the Company’s proprietary GPCR structure determination technologies, including application of such technologies to the development of potential modulators directed to an undisclosed GPCR target.  The Company was responsible for conducting certain research activities with respect to the undisclosed GPCR target and sharing certain information in pursuit of potential drug candidate leads. In January 2011, as consideration for technology access over the term, Lilly paid the Company an upfront, non-refundable fee of $5.0 million and upon the successful achievement of milestones related to the identification of Structurally Enabled Hits, or SEHs, as defined, to an undisclosed GPCR target, the Company was eligible to receive from Lilly additional payments.
	The Company’s collaborative arrangement with Lilly was subject to the previous accounting for multiple-element arrangements and was analyzed to determine whether the elements within the agreement could be separated or whether they must be accounted for as a single unit of accounting. Under this arrangement, management determined there was not objective and reliable evidence of fair value of the undelivered element items (which for the Company was research and development activities). Consideration received was recognized under the arrangement as revenue on a straight-line basis over the estimated period of performance, which for this contract was the contract term.
	The agreement expired on December 31, 2012, and each of the Company and Lilly retain the right to use the research and development know-how for future research activities. The Company does not expect to receive any future milestone payments from Lilly.

Term_Loan_and_Security_Agreeme

Term Loan and Security Agreement	9 Months Ended
	Sep. 30, 2013
Term Loan and Security Agreement
Term Loan and Security Agreement	5.              Term Loan and Security Agreement
	On April 19, 2013, the Company entered into a credit and security agreement with MidCap Funding III, LLC allowing for borrowings up to $30.0 million. The credit and security agreement provides for the loan to be issuable in three tranches:
	·                  the first tranche of $10.0 million was available to the Company at the closing of the credit agreement (of which the Company drew down $5.0 million and of which the Company has another $5.0 million available to it through March 31, 2014);
	·                  the second tranche of $10.0 million is available to the Company through March 31, 2014 if the Company enters into certain equity or financing transactions in which the Company receives minimum net proceeds of at least $40.0 million through a qualifying initial public offering, a private placement and/or a corporate or research partnership for development of the Company’s product candidates (which condition was satisfied by the IPO), and if the Company is planning to conduct development activities for a Phase 2 study for RPC4046 and has retained rights to RPC4046 under the license agreement with AbbVie Bahamas Ltd. and AbbVie Inc. (referred to collectively as AbbVie, and formerly a part of Abbott Laboratories); and
	·                  the third tranche of $10.0 million is available to the Company through December 31, 2014 if the Company has consummated an initial public offering for at least $60.0 million in proceeds (which condition was satisfied by the IPO), and
	·                  the Company has received positive data from the Phase 2 trial of RPC1063 in RMS,
	·                  the Company has an ongoing Phase 3 trial of RPC1063 in RMS, and
	·                  the Company has retained rights to RPC4046 under the license agreement with AbbVie.
	The interest rate under the credit and security agreement is 8.25%, and there is an interest only period until August 1, 2014, followed by a 34-month principal and interest period. Any unpaid amounts mature and become payable on May 1, 2017. Pursuant to the credit and security agreement, the Company provided a first priority security interest in all existing and after-acquired assets (excluding intellectual property owned by the Company, which is subject to a negative pledge arrangement).
	The loan was recorded at its initial carrying value of $5.0 million, less the debt discount of $0.2 million.  The debt discount included an initial fee paid to the lender and certain reimbursed costs of the transaction.  At the time of final payment of the loan, the Company must also pay an exit fee of $350,000 to the lender.  In addition, if the Company’s repayment obligation is accelerated following an event of default, or if the Company elects to prepay any portion of the loan, the Company must also pay a prepayment fee of 3% of the principal being repaid (dropping to 2% after August 18, 2014 then to 1% after December 18, 2015).  The debt discount and the exit fee are being accreted to interest expense over the loan term.
	At September 30, 2013, the future principal payments due under the loan agreement are as follows (in thousands):
	Year ended December 31, 2013 (three months remaining)	$	—
	Year ended December 31, 2014	735
	Year ended December 31, 2015	1,765
	Year ended December 31, 2016	1,765
	Year ended December 31, 2017	735
	Total future principal payments due under loan agreement	$	5,000

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies
Commitments and Contingencies	6.              Commitments and Contingencies
	License Agreements
	The Company has license agreements with The Scripps Research Institute, or TSRI, that require it to make annual license maintenance payments and future payments upon the success of licensed products that include milestones and/or royalties. Royalties are expensed as incurred and are included in research and development in our condensed consolidated statements of operations and comprehensive loss.
	S1P1R Modulators License Agreement. In April 2009, the Company entered into a License Agreement with TSRI whereby the Company received (i) an exclusive worldwide license under the Licensed Patent Rights, as defined, for sphingosine 1-phosphate 1 receptor (S1P1R) modulators and (ii) a non-exclusive worldwide license to the Licensed Materials, as defined. In consideration, the Company:
	·                  issued 17,930 and 7,276 shares of common stock to TSRI in May and November 2009, respectively,
	·                  agreed to pay a nominal annual maintenance fee,
	·                  is responsible for paying royalties on annual net sales of Licensed Product, as defined, ranging between 1.5% and 2.0%, for Licensed Product until such time as the expiration of the last valid claim,
	·                  is responsible for paying royalties ranging between 0.75% and 1.0%, on annual net sales of Non-Patent Product, as defined, until such time as:
	·                  one or more generic versions of such Non-Patent Product are commercially sold, and
	·                  the Company demonstrates to TSRI that sales of such generic products account for a specific percentage of aggregate unit sales in a calendar quarter,
	·                  is responsible for paying product development milestone payments not to exceed $4.4 million, and
	·                  is responsible for paying a percentage of any sublicense revenue payments received by the Company.
	Royalties paid to TSRI in connection with this agreement were not significant during either 2012 or 2013.
	Technology Platform License Agreement. In June 2009, the Company entered into a Technology Platform License Agreement with TSRI whereby the Company received (i) an exclusive worldwide license under the Licensed Patent Rights, as defined, and (ii) a non-exclusive worldwide license under the Know-How, as defined. In consideration, the Company:
	·                  issued 17,930 and 7,276 shares of common stock to TSRI in June and November 2009, respectively,
	·                  agreed to pay a nominal annual maintenance fee beginning after June 18, 2011, which shall be credited against running royalties during the term of the Agreement,
	·                  shall pay running royalties at a de minimus rate of annual net sales of Company Products, as defined, until June 18, 2019,
	·                  shall pay product development milestone payments not to exceed approximately $1.0 million, and
	·                  shall make non-creditable, non-refundable Aggregate Technology Income (ATI), as defined, payments of
	·                  7.5% of the first $100 million of cumulative ATI, except that no ATI payments shall be due on the first $2.5 million in cumulative ATI, and
	·                  a reduced percentage of that portion of cumulative ATI that is in excess of $100 million.
	All product development milestone and ATI payments are payable up to June 18, 2027.  Royalties paid to TSRI in connection with this agreement were not significant during either 2012 or 2013.
	Operating Lease
	The Company’s lease to rent laboratory and office space in San Diego, California commenced in March 2008 and as amended, expires in October 2014. The Company also has two options to extend the lease for successive three-year periods. Under the terms of the lease, the Company maintains a letter of credit totaling $0.1 million which is included in other assets in the accompanying condensed consolidated balance sheets. The Company recognizes minimum rent payments and escalation clauses on a straight-line basis over the lease term of March 2008 through October 2014. The Company accounts for the difference between the minimum lease payments and the straight-line amount as deferred rent. The Company also pays property taxes, maintenance and insurance, in addition to rent.
	Rent expense for the three and nine months ended September 30, 2012 and 2013 was $0.2 million and $0.6 million, respectively.
	Litigation
	From time to time, the Company may be involved in various lawsuits, legal proceedings, or claims that arise in the ordinary course of business. Management does not believe any legal proceedings or claims pending at September 30, 2013, will have, individually or in the aggregate, a material adverse effect on its business, liquidity, financial position or results of operations. Litigation, however, is subject to inherent uncertainties, and an adverse result in these or other matters may arise from time to time that may harm the Company’s business.

Convertible_Preferred_Stock_Co

Convertible Preferred Stock, Common Stock and Warrants	9 Months Ended
	Sep. 30, 2013
Convertible Preferred Stock, Common Stock and Warrants
Convertible Preferred Stock, Common Stock and Warrants	7.              Convertible Preferred Stock, Common Stock and Warrants
	Reverse Stock Split
	On April 25, 2013, the Company implemented a 1-for-7.5 reverse stock split of its outstanding common stock. The accompanying condensed consolidated financial statements give retroactive effect to the reverse split for all periods presented.
	Convertible Preferred Stock
	Prior to the IPO, the Company was authorized to issue 39,375,697 shares of Series A convertible preferred stock and 48,543,700 shares of Series B convertible preferred stock. Prior to its conversion in the IPO, the Company’s convertible preferred stock was classified as temporary equity in the accompanying condensed consolidated balance sheet at December 31, 2012 instead of in stockholders’ deficit in accordance with authoritative guidance for the classification and measurement of potentially redeemable securities. Upon certain change in control events that were outside of the Company’s control, including liquidation, sale or transfer of control of the Company, holders of the convertible preferred stock could have caused its redemption.
	Issuance of Series B Convertible Preferred Stock
	In February and March 2012, the Company issued 12,357,561 shares of Series B Convertible Preferred Stock under a Series B Preferred Stock Purchase Agreement at $1.03 per share for net proceeds of $12.5 million.
	On February 19, 2013, pursuant to the terms of the Series B Preferred Stock Purchase Agreement dated as of February 3, 2012, the Company closed a second tranche financing for 12,357,561 shares of Series B Convertible Preferred Stock, at $1.03 per share for net proceeds of $12.7 million.
	On March 27, 2013, pursuant to the terms of the Series B Preferred Stock Purchase Agreement dated as of February 3, 2012, the Company closed a third tranche financing for 8,238,377 shares of Series B Convertible Preferred Stock, at $1.03 per share, for net proceeds of $8.4 million. The Series B Convertible Preferred Stock issued in the third tranche financing was sold at a price per share below the reassessed deemed fair value of the Company’s common stock at that time. Accordingly, the Company recorded a deemed dividend of $2.1 million during the first quarter of 2013 associated with the issuance of such shares, which is equal to the number of shares of Series B Convertible Preferred Stock sold on that date multiplied by the difference between the estimated value of the underlying common stock and the Series B conversion price per share on that date.
	Conversion of Preferred Stock
	On May 14, 2013, the 72,329,196 outstanding shares of Convertible Preferred Stock automatically converted into an aggregate of 9,643,877 shares of common stock immediately prior to the closing of the IPO.
	Preferred Stock
	In May 2013, the Company filed an amended and restated certificate of incorporation to authorize 10,000,000 shares of undesignated preferred stock.
	Common Stock
	In July 2009, in conjunction with the formation of Receptos, the Company sold 279,998 shares of restricted common stock to certain officers with a per share price of approximately $0.08, for gross proceeds of approximately $21,000. The restrictions will lapse as follows: (i) 199,998 vested over a four-year period ending May 11, 2013; and (ii) 80,000 shares were subject to both performance-based criteria and time-based vesting conditions. The milestones associated with these 80,000 shares had been met as of December 31, 2012 and these shares are now subject to only time-based vesting through November 19, 2015. As of September 30, 2013, 25,834 shares associated with performance-based criteria were subject to repurchase by the Company.
	The Company’s 2008 Stock Plan, or the 2008 Plan, allows for early exercise of option awards under the plan. As of September 30, 2013, options for the purchase of 982,465 shares of common stock had been exercised, of which 361,206 were unvested and subject to repurchase. Under the authoritative guidance, early exercise is not considered an exercise for accounting purposes and, therefore, any payment for unvested shares is recognized as a liability at the original exercise price. The early exercise liability was $0.2 million and $0.1 million as of December 31, 2012 and September 30, 2013, respectively.
	Common Stock Warrants
	As of December 31, 2012, warrants for the purchase of 342,854 shares of the Company’s common stock were outstanding. During the first quarter of 2013, all previously outstanding warrants were exercised for proceeds of approximately $26,000.
	Initial Public Offering
	In May 2013, the Company completed the IPO of 5,933,277 shares of common stock at an offering price of $14.00 per share, which included the exercise by the underwriters of their option to purchase 733,277 additional shares of common stock. The Company received net proceeds of approximately $75.0 million, after deducting underwriting discounts, commissions and offering-related transaction costs.

StockBased_Compensation_and_Eq

Stock-Based Compensation and Equity Plans	9 Months Ended
	Sep. 30, 2013
Stock-Based Compensation and Equity Plans
Stock-Based Compensation and Equity Plans	8.              Stock-Based Compensation and Equity Plans
	2013 Stock Incentive Plan
	Prior to the completion of the IPO, the Company issued stock options under its 2008 Plan.  Effective upon the closing of the IPO, the Company’s board of directors and stockholders approved the 2013 Stock Incentive Plan (the 2013 Plan). The number of shares of common stock available for future grant under the 2013 Plan upon its approval was 1,146,600 shares plus (i) the number of shares subject to outstanding awards under the 2008 Plan that are subsequently forfeited or terminated for any reason before being exercised or settled and (ii) the number of shares subject to vesting restrictions under the 2008 Plan that are subsequently forfeited.  In addition, the number of shares of common stock that may be issued under the 2013 Plan is subject to an automatic annual increase equal to the lesser of (x) four percent of the outstanding shares on the last day of the immediately preceding fiscal year or (y) if the Company’s board acts prior to the first day of the fiscal year, such other amount that the board determines for purposes of the annual increase for that fiscal year.
	The 2013 Plan provides for the granting of incentive stock options within the meaning of Section 422 of the Internal Revenue Code to employees and the granting of nonstatutory stock options to employees, non-employee directors, advisors and consultants.  The 2013 Plan also provides for the granting of restricted stock, stock appreciation rights, stock unit and cash-based awards to employees, non-employee directors, advisors and consultants.  The Company has issued under the 2008 Plan and intends to continue to issue under the 2013 Plan both time-based and performance-based stock option and restricted stock awards. Time-based awards generally vest over a four-year period commencing on the first anniversary of the date of grant, while performance-based awards generally vest 25% upon achievement of a milestone event, with monthly time-based vesting over the subsequent 36 months. Milestone events are specific to the Company’s corporate goals, including but not limited to the first dosing of patients in the Company’s clinical trials. Awards generally expire ten years from the date of grant.
	The following table summarizes stock-based compensation expense for equity awards to employees and non-employees (in thousands):
		Three months ended				Nine months ended
		September 30,				September 30,
		2012		2013		2012		2013
	Included in research and development expense	$	43	$	499	$	125	$	791
	Included in general and administrative expense	7		638		21		875
	Total stock-based compensation expense	$	50	$	1,137	$	146	$	1,666
	Employee Stock Purchase Plan
	Effective upon the closing of the IPO, the Company’s board of directors and the stockholders approved the 2013 Employee Stock Purchase Plan (the ESPP). Upon implementation, the Company can issue up to 160,000 shares under the ESPP. The ESPP is subject to an automatic annual increase equal to the lesser of (i) one percent of the outstanding capital stock on each January 1 or (ii) an amount determined by the Company’s board of directors.

RelatedParty_Transactions

Related-Party Transactions	9 Months Ended
	Sep. 30, 2013
Related-Party Transactions
Related-Party Transactions	9.              Related-Party Transactions
	In May 2009, the Company entered into consulting agreements with certain of its founders. Under the terms of these agreements the founders would serve in an advisory capacity with respect to the Company’s research and development activities. As compensation for services provided, the founders received (i) a quarterly consulting fee, (ii) an aggregate of 199,999 shares of the Company’s common stock, subject to certain vesting restrictions, and (iii) options to acquire an aggregate of 100,000 shares of common stock, subject to certain performance-based criteria. Compensation earned under these agreements was $33,000 and $135,000 for the three and nine months ended September 30, 2012, respectively, and $15,000 and $81,000 for the three and nine months ended September 30, 2013, respectively.
	In February 2012, February 2013 and March 2013, in connection with the closing of the Company’s Series B Convertible Preferred Stock financing, a sister company of the Company’s landlord purchased an aggregate of 2,912,621 shares of Series B Convertible Preferred Stock for cash proceeds of $3.0 million.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Summary of Significant Accounting Policies
Use of Estimates	Use of Estimates
	The preparation of the Company’s condensed consolidated financial statements and accompanying notes in conformity with GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities.  The most significant estimates in the Company’s condensed consolidated financial statements relate to clinical trial accruals, revenue recognition and stock-based compensation. Although these estimates and assumptions are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately differ materially from these estimates and assumptions.
Segment Reporting	Segment Reporting
	Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment operating primarily in the US.
Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company classifies time deposits and other investments that are highly liquid and have maturities of 90 days or less at the date of purchase as cash equivalents. The carrying amounts approximate fair value due to the short maturities of these instruments. Cash and cash equivalents include cash in checking and money market accounts.
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	The carrying amounts of all cash equivalents, accounts payable and accrued liabilities are reasonable estimates of their fair value because of the short nature of these items.
	The valuation of assets and liabilities are subject to fair value measurements using a three tiered approach and fair value measurement is classified and disclosed by the Company in one of the following three categories:
	Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
	Level 2: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability;
	Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
	Cash and cash equivalents are measured at fair value on a recurring basis. As of December 31, 2012 and September 30, 2013, cash equivalents are classified within the Level 1 designation as noted above. As of December 31, 2012 and September 30, 2013, the carrying amount of cash equivalents was $5.3 million and $77.0 million, respectively, which approximates fair value and was determined based upon Level 1 inputs. Cash equivalents consisted of funds held in money market accounts. As of December 31, 2012 and September 30, 2013, the Company does not hold any Level 2 or Level 3 financial instruments.
Concentrations of Credit Risk	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial position of the depository institutions in which those deposits are held. The Company maintains cash equivalents with two financial institutions. The Company invests excess cash in money market accounts. Additionally, the Company has established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.
Property and Equipment	Property and Equipment
	The Company records its property and equipment at cost and computes depreciation using the straight-line method over the estimated useful lives of the assets (generally three years). The Company amortizes leasehold improvements over the lease term or the useful life of the improvement, whichever is shorter (including any renewal periods that are deemed to be reasonably assured). The Company expenses repair and maintenance costs that do not improve service potential or extend economic life as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets
	The Company reviews property and equipment for impairment on an annual basis and whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. An impairment loss would be recognized when estimated future undiscounted cash flows relating to the asset are less than its carrying amount. An impairment loss is measured as the amount by which the carrying amount of an asset exceeds its fair value. While the Company’s current and historical operating losses and negative cash flows are possible indicators of impairment, management believes that the future cash flows to be generated by these assets support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses through September 30, 2013.
Income Taxes	IncomeTaxes
	The Company follows the accounting guidance on accounting for uncertainty in income taxes. The guidance prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position.
	The Company uses the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made.
Revenue Recognition	Revenue Recognition
	The Company enters into arrangements with pharmaceutical and biotechnology partners that may involve multiple deliverables. The Company’s arrangements may contain upfront payments, license fees for research and development arrangements, research and development funding and milestone payments under collaborative agreements. Each deliverable in the arrangement is evaluated to determine whether it meets the criteria to be accounted for as a separate unit of accounting or whether it should be combined with other deliverables. Revenue is recognized separately for each unit of accounting when all four of the following criteria are met: (i) persuasive evidence that an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the selling price is fixed or determinable; and (iv) collectability is reasonably assured.
	Upfront Fees. When management determines the Company has a single unit of accounting under its collaborative arrangements, upfront fees received for collaborative agreements are recognized ratably over the expected performance period under each respective arrangement. The Company’s collaborations to date have had stated periods of performance; however, the agreement with Ono Pharmaceutical Co., Ltd., or Ono, contains an option whereby Ono may choose to extend the development period. As a result, management makes its best estimate of the period over which the Company expects to fulfill its performance obligations under that agreement. Any amounts received under the agreements in advance of performance, if deemed substantive, are recorded as deferred revenue and recognized as revenue as the Company completes its performance obligations.
	Milestones. The Company evaluates all milestones at the beginning of the agreement to determine if they meet the definition of a substantive milestone. Revenue is recognized from milestone payments when earned, provided that (i) the milestone event is substantive in that it can only be achieved based in whole or in part on either the Company’s performance or on the occurrence of a specific outcome resulting from the Company’s performance and its achievability was not reasonably assured at the inception of the agreement, (ii) the Company does not have ongoing performance obligations related to the achievement of the milestone and (iii) it would result in the receipt of additional payments. A milestone payment is considered substantive if all of the following conditions are met: (i) the milestone payment is non-refundable; (ii) achievement of the milestone was not reasonably assured at the inception of the arrangement; (iii) substantive effort is involved to achieve the milestone; and (iv) the amount of the milestone payments appears reasonable in relation to the effort expended, the other milestones in the arrangement and the related risk associated with the achievement of the milestone.
	The Company’s collaboration arrangements provide for payments upon the achievement of research milestones, such as providing structure solutions with candidate compounds for certain targets. Given the challenges inherent in determining high resolution structure solutions for G protein-coupled receptor (GPCR) targets, there was substantial uncertainty whether any such milestones would be achieved at the time the Company entered into these collaboration arrangements. In addition, the Company evaluated whether the research milestones met the remaining criteria to be considered substantive. As a result of its analysis, management considers most of the Company’s research milestones to be substantive and, accordingly, it expects to recognize as revenue future payments received from such milestones as each milestone is achieved. For those milestones that in management’s judgment did not meet the additional criteria to be considered substantive, these payments are deferred upon achievement and recognized ratably in the condensed consolidated statements of operations and comprehensive loss over the remaining estimated period of its performance.
	Deferred Revenue. Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying condensed consolidated balance sheets. Amounts not expected to be recognized within the next 12 months are classified as non-current deferred revenue.
Research and Development	Research and Development
	Research and development costs are expensed as incurred.
Patent Expenses	Patent Expenses
	Costs related to filing and pursuing patent applications are recorded as general and administrative expense since recoverability of such expenditures is uncertain.
Stock-Based Compensation	Stock-Based Compensation
	The Company accounts for stock-based compensation expense related to stock options granted to employees and members of its board of directors by estimating the fair value of each stock option on the date of grant using the Black-Scholes options-pricing model net of estimated forfeitures. For awards subject to time-based vesting conditions, stock-based compensation expense is recognized using the straight-line method. In accordance with the authoritative accounting literature, options subject to both performance and time-based vesting conditions are expensed using an accelerated multiple-option approach. Under the accelerated multiple-option approach (also known as the graded-vesting method), compensation expense is recognized over the requisite service period for each separately vesting tranche of the award as though the award was in substance multiple awards, resulting in accelerated expense recognition during the earlier vesting periods.
	The Company accounts for stock options granted to non-employees using the fair value approach. Stock options granted to non-employees are subject to periodic revaluation over their vesting terms.
Comprehensive Loss	Comprehensive Loss
	Comprehensive loss is defined as the change in equity during a period from transactions and other events and/or circumstances from non-owner sources. Comprehensive loss is equal to net loss for all periods presented.
Net Loss per Share	Net Loss per Share
	Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Excluded from the weighted-average number of shares outstanding are shares which have been issued upon the early exercise of stock options and are subject to future vesting and unvested restricted stock totaling 1.0 million and 0.6 million shares as of September 30, 2012 and 2013, respectively. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of convertible preferred stock, stock options and warrants.  Basic and diluted net loss per share are equivalent because the Company has incurred a net loss in all periods presented causing any potentially dilutive securities to be anti-dilutive. The following table summarizes the weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share (in thousands):
		Three months ended		Nine months ended
		September 30,		September 30,
		2012	2013	2012	2013
	Convertible preferred stock	6,898	—	6,706	4,061
	Common stock equivalents:
	Options to purchase common stock	154	1,107	224	578
	Warrants to purchase common stock	343	—	358	—
	Total	7,395	1,107	7,888	4,639
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In February 2013, the Financial Accounting Standards Board issued an accounting standard update to require reclassification adjustments from other comprehensive income to be presented either in the financial statements or in the notes to the financial statements. This accounting standard became effective for the Company beginning in the first quarter of fiscal 2013, and its adoption did not have any impact on the Company’s consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2013
Summary of Significant Accounting Policies
Summary of the weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share	The following table summarizes the weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share (in thousands):
		Three months ended		Nine months ended
		September 30,		September 30,
		2012	2013	2012	2013
	Convertible preferred stock	6,898	—	6,706	4,061
	Common stock equivalents:
	Options to purchase common stock	154	1,107	224	578
	Warrants to purchase common stock	343	—	358	—
	Total	7,395	1,107	7,888	4,639

Balance_Sheet_Details_Tables

Balance Sheet Details (Tables)	9 Months Ended
	Sep. 30, 2013
Balance Sheet Details
Summary of major classes of prepaid expenses and other current assets	The following table summarizes major classes of prepaid expenses and other current assets (in thousands):
		December 31,			September 30,
		2012			2013
	Prepaid contract research	$	435		$	—
	Prepaid maintenance agreements	92			98
	Prepaid rent	69			79
	Prepaid insurance	62			343
	Prepaid other	128			145
	Total	$	786		$	665
Summary of major classes of property and equipment	The following table summarizes major classes of property and equipment (in thousands):
		Useful		December 31			September 30,
		life		2012			2013
	Laboratory equipment	3 years		$	2,940		$	3,004
	Computer equipment and software	3 years		226			232
	Leasehold improvements	7 years		854			854
				4,020			4,090
	Less accumulated depreciation and amortization			(3,471		)	(3,732		)
	Property and equipment, net			$	549		$	358
Summary of major classes of accrued expenses	The following table summarizes major classes of accrued expenses (in thousands):
		December 31			September 30,
		2012			2013
	Clinical trial accrual	$	1,289		$	5,870
	Accrued royalty payable	176			—
	Other accrued liabilities	217			2,392
	Total	$	1,682		$	8,262

Collaborative_Arrangements_Tab

Collaborative Arrangements (Tables)	9 Months Ended
	Sep. 30, 2013
Collaborative Arrangements
Schedule of recognized collaboration revenue	The Company recognized collaborative revenue under these arrangements as follows (in thousands):
		Three months ended				Nine months ended
		September 30,				September 30,
	Partner	2012		2013		2012		2013
	Ono Pharmaceutical Co., Ltd.	$	1,174	$	1,142	$	2,850	$	3,868
	Eli Lilly and Company	620		—		1,880		—
	Other	—		—		79		—
	Total	$	1,794	$	1,142	$	4,809	$	3,868

Term_Loan_and_Security_Agreeme1

Term Loan and Security Agreement (Tables)	9 Months Ended
	Sep. 30, 2013
Term Loan and Security Agreement
Schedule of future principal payments due under the loan agreement	At September 30, 2013, the future principal payments due under the loan agreement are as follows (in thousands):
	Year ended December 31, 2013 (three months remaining)	$	—
	Year ended December 31, 2014	735
	Year ended December 31, 2015	1,765
	Year ended December 31, 2016	1,765
	Year ended December 31, 2017	735
	Total future principal payments due under loan agreement	$	5,000

StockBased_Compensation_and_Eq1

Stock-Based Compensation and Equity Plans (Tables)	9 Months Ended
	Sep. 30, 2013
Stock-Based Compensation and Equity Plans
Schedule of total stock-based compensation expense for equity awards to employees and non employees	The following table summarizes stock-based compensation expense for equity awards to employees and non-employees (in thousands):
		Three months ended				Nine months ended
		September 30,				September 30,
		2012		2013		2012		2013
	Included in research and development expense	$	43	$	499	$	125	$	791
	Included in general and administrative expense	7		638		21		875
	Total stock-based compensation expense	$	50	$	1,137	$	146	$	1,666

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Organization and Basis of Presentation
Accumulated deficit	($80,665)	($47,589)

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
	item	Recurring basis	Recurring basis
		Level 1	Level 1
Segment Reporting
Number of operating segments	1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Carrying amount of cash equivalents		$77	$5.30
Concentrations of Credit Risk
Number of financial institutions in which the entity maintains cash equivalents	2
Property and Equipment
Estimated useful lives	3 years
Revenue Recognition
Number of criteria for considering revenue recognition separately for each element	4

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Details 2)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Summary of Significant Accounting Policies
Shares excluded from the weighted-average number of shares outstanding, which have been issued upon the early exercise of stock options and are subject to future vesting and unvested restricted stock	600,000	1,000,000	600,000	1,000,000
Net loss per share
Weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share	1,107,000	7,395,000	4,639,000	7,888,000
Convertible preferred stock
Net loss per share
Weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share		6,898,000	4,061,000	6,706,000
Options to purchase common stock
Net loss per share
Weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share	1,107,000	154,000	578,000	224,000
Warrants to purchase common stock
Net loss per share
Weighted-average anti-dilutive securities excluded from the calculation of diluted net loss per share		343,000		358,000

Balance_Sheet_Details_Details

Balance Sheet Details (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Prepaid Expenses and Other Current Assets
Prepaid contract research					$435
Prepaid maintenance agreements	98		98		92
Prepaid rent	79		79		69
Prepaid insurance	343		343		62
Prepaid other	145		145		128
Total	665		665		786
Property and equipment
Useful life			3 years
Property and equipment, gross	4,090		4,090		4,020
Less accumulated depreciation and amortization	-3,732		-3,732		-3,471
Property and equipment, net	358		358		549
Depreciation and amortization expense	100	100	261	518
Accrued Expenses
Clinical trial accrual	5,870		5,870		1,289
Accrued royalty payable					176
Other accrued liabilities	2,392		2,392		217
Total	8,262		8,262		1,682
Laboratory equipment
Property and equipment
Useful life			3 years
Property and equipment, gross	3,004		3,004		2,940
Computer equipment and software
Property and equipment
Useful life			3 years
Property and equipment, gross	232		232		226
Leasehold improvements
Property and equipment
Useful life			7 years
Property and equipment, gross	$854		$854		$854

Collaborative_Arrangements_Det

Collaborative Arrangements (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

1 Months Ended

3 Months Ended

9 Months Ended

1 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Jan. 31, 2011

Dec. 31, 2010

Sep. 30, 2012

Sep. 30, 2012

Sep. 30, 2012

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Co-exclusive collaboration agreement

Ono Pharmaceutical Co., Ltd.

Ono Pharmaceutical Co., Ltd.

Ono Pharmaceutical Co., Ltd.

Ono Pharmaceutical Co., Ltd.

Ono Pharmaceutical Co., Ltd.

Ono Pharmaceutical Co., Ltd.

Eli Lilly and Company

Eli Lilly and Company

Eli Lilly and Company

Eli Lilly and Company

Other

item

Maximum

Collaborative arrangements

Total

$1,142,000

$1,794,000

$3,868,000

$4,809,000

$1,142,000

$1,794,000

$3,868,000

$4,809,000

$1,142,000

$1,174,000

$3,868,000

$2,850,000

$620,000

$1,880,000

$79,000

Period of the collaboration agreement

30 months

2 years

Upfront, non-refundable fee received

2,500,000

5,000,000

Number of units of accounting

1

Milestone payments, which did not meet the definition of a substantive milestone, received and amortized

1,500,000

Milestone payments, which met all criteria necessary for concluding the milestones to be substantive, received and recognized

0

300,000

0

Future potential substantive milestones based upon the entity's research efforts

2,000,000

Future potential development milestones based on Ono's efforts

15,000,000

Research and development support payments recognized

700,000

800,000

2,400,000

1,700,000

Deferred revenues

$1,500,000

$1,500,000

Term_Loan_and_Security_Agreeme2

Term Loan and Security Agreement (Details) (USD $)	9 Months Ended		0 Months Ended		0 Months Ended
	Sep. 30, 2013	Apr. 19, 2013	Apr. 19, 2013	Apr. 19, 2013	Apr. 19, 2013	Apr. 19, 2013
			Credit and security agreement	First tranche	Second tranche	Third tranche
			item
Term loan and security agreement
Maximum borrowing capacity			$30,000,000	$10,000,000	$10,000,000	$10,000,000
Number of tranches in which loan issuable			3
Amount drawn				5,000,000
Remaining borrowing capacity				5,000,000
Minimum net proceeds through a qualifying initial public offering, a private placement and/or a corporate or research partnership for borrowings					40,000,000	60,000,000
Interest rate (as a percent)			8.25%
Principal and interest period			34 months
Debt discount		200,000
Exit fee		350,000
Prepayment fee percentage			3.00%
Prepayment fee percentage after August 18, 2014			2.00%
Prepayment fee percentage after December 18, 2015			1.00%
Future principal payments due under the loan agreement
Year ended December 31, 2014	735,000
Year ended December 31, 2015	1,765,000
Year ended December 31, 2016	1,765,000
Year ended December 31, 2017	735,000
Total future principal payments due under loan agreement	$5,000,000

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	1 Months Ended
In Millions, except Share data, unless otherwise specified	31-May-13	Nov. 30, 2009	31-May-09	Apr. 30, 2009	Apr. 30, 2009	Nov. 30, 2009	Jun. 30, 2009	Jun. 30, 2009
		S1P1R Modulators License Agreement	S1P1R Modulators License Agreement	S1P1R Modulators License Agreement	S1P1R Modulators License Agreement	Technology Platform License Agreement	Technology Platform License Agreement	Technology Platform License Agreement
		TSRI	TSRI	TSRI	TSRI	TSRI	TSRI	TSRI
				Minimum	Maximum			Maximum
				item
Commitments and contingencies
Common stock issued (in shares)	5,933,277	7,276	17,930			7,276	17,930
Percentage of royalties payable on annual net sales of Licensed Product				1.50%	2.00%
Percentage of royalties payable on annual net sales of Non-Patent Product				0.75%	1.00%
Number of generic versions of Non-Patent Product commercially sold				1
Product development milestone payments					$4.40			$1
Payment of ATI as a percentage of the first $100 million of cumulative ATI							7.50%
Amount of ATI on the first $2.5 million of cumulative ATI							0
Amount of the first cumulative ATI for calculating the payments percentage of ATI							100
Amount of the first cumulative ATI on which no ATI payments shall be due							2.5
Threshold amount of cumulative ATI for determination of reduced percentage for the payments of ATI							$100

Commitments_and_Contingencies_1

Commitments and Contingencies (Details 2) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
			item
Operating Lease
Number of options available for extension of lease term			2
Extended term of operating lease			3 years
Amount of letter of credit maintained	$0.10		$0.10
Rent expense	$0.20	$0.20	$0.60	$0.60

Convertible_Preferred_Stock_Co1

Convertible Preferred Stock, Common Stock and Warrants (Details) (USD $)

0 Months Ended

9 Months Ended

0 Months Ended

0 Months Ended

2 Months Ended

3 Months Ended

In Thousands, except Share data, unless otherwise specified

Apr. 25, 2013

Sep. 30, 2013

Sep. 30, 2012

31-May-13

14-May-13

Sep. 30, 2013

Dec. 31, 2012

Mar. 27, 2013

Feb. 19, 2013

Mar. 31, 2012

Mar. 31, 2013

Sep. 30, 2013

Dec. 31, 2012

Convertible preferred stock

Series A

Series A

Series B

Series B

Series B

Series B

Series B

Series B

Convertible Preferred Stock

Reverse stock split ratio

7.5

Shares Authorized

0

39,375,697

0

48,543,700

Aggregate shares of preferred stock issued

8,238,377

12,357,561

12,357,561

Issue price (in dollars per share)

$1.03

$1.03

$1.03

Net cash proceeds from issuance

$21,192

$12,556

$8,400

$12,700

$12,500

Deemed dividend

$2,056

$2,100

Outstanding shares of convertible preferred stock

72,329,196

0

39,375,697

0

12,357,561

Number of shares of common stock issued against conversion of preferred stock

9,643,877

Preferred Stock

Authorized shares of undesignated preferred stock

10,000,000

10,000,000

Convertible_Preferred_Stock_Co2

Convertible Preferred Stock, Common Stock and Warrants (Details 2) (USD $)	Sep. 30, 2013	31-May-13	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012	Jul. 31, 2009	Jul. 31, 2009	Dec. 31, 2012	Sep. 30, 2013	Jul. 31, 2009
				Option awards	Option awards	Officers	Officers	Officers	Officers	Officers
						Restricted common stock	Restricted common stock	Restricted common stock	Restricted common stock	Restricted common stock
							Time-Based Awards	Time-Based Awards	Performance-Based Awards	Performance and Time-Based Awards
Common Stock
Shares sold						279,998	199,998			80,000
Share price (in dollars per share)		$14				$0.08
Gross proceeds from sale of shares						$21,000
Vesting period							4 years
Shares with performance-based criteria met, now subject only to time-based vesting								80,000
Shares subject to repurchase									25,834
Options for the purchase of shares of common stock exercised				982,465
Options unvested and subject to repurchase (in shares)				361,206
Early exercise liability	$132,000		$188,000	$100,000	$200,000

Convertible_Preferred_Stock_Co3

Convertible Preferred Stock, Common Stock and Warrants (Details 3) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended
	31-May-13	Mar. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Convertible Preferred Stock, Common Stock and Warrants
Warrants for the purchase of shares of common stock outstanding (in shares)				342,854
Proceeds from warrants exercised		$26,000
Initial Public Offering
Shares of common stock sold in the IPO	5,933,277
Share price (in dollars per share)	$14
Partial exercise of an option by the underwriters to purchase additional shares of common stock	733,277
Net proceeds received			$75,009,000

StockBased_Compensation_and_Eq2

Stock-Based Compensation and Equity Plans (Details)	9 Months Ended
	Sep. 30, 2013
2013 Plan
Share Awards
Shares of common stock available for future grant	1,146,600
Automatic annual increase in number of shares that may be issued under plan as percentage of outstanding shares	4.00%
Expiration term of awards	10 years
2013 Plan | Time-Based Awards
Share Awards
Vesting period	4 years
2013 Plan | Performance-based Awards
Share Awards
Vesting period	36 months
Vesting percentage upon achievement of a milestone event	25.00%
2013 employee stock purchase plan
Share Awards
Shares of common stock reserved for future issuance	160,000
Automatic annual increase in number of shares that may be issued under plan as percentage of outstanding shares	1.00%

StockBased_Compensation_and_Eq3

Stock-Based Compensation and Equity Plans (Details 2) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
2013 Stock Incentive Plan
Total stock-based compensation expense	$1,137	$50	$1,666	$146
Included in research and development expense
2013 Stock Incentive Plan
Total stock-based compensation expense	499	43	791	125
Included in general and administrative expense
2013 Stock Incentive Plan
Total stock-based compensation expense	$638	$7	$875	$21

RelatedParty_Transactions_Deta

Related-Party Transactions (Details) (USD $)	9 Months Ended		0 Months Ended		2 Months Ended	1 Months Ended	3 Months Ended		9 Months Ended		14 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Mar. 27, 2013	Feb. 19, 2013	Mar. 31, 2012	31-May-09	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2013
			Series B Convertible Preferred Stock	Series B Convertible Preferred Stock	Series B Convertible Preferred Stock	Founders	Founders	Founders	Founders	Founders	Sister company of the Company's landlord
											Series B Convertible Preferred Stock
Related-party transactions
Shares of common stock issued for services received						199,999
Options to acquire shares of common stock for services received (in shares)						100,000
Compensation paid under agreements							$15,000	$33,000	$81,000	$135,000
Aggregate shares of preferred stock issued			8,238,377	12,357,561	12,357,561						2,912,621
Net cash proceeds from issuance	$21,192,000	$12,556,000	$8,400,000	$12,700,000	$12,500,000						$3,000,000