Alpine Immune Sciences (ALPN) 10-Q 14 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 04, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Alpine Immune Sciences, Inc.
Trading Symbol	ALPN
Entity Central Index Key	1,626,199
Current Fiscal Year End Date	--12-31
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Entity Filer Category	Smaller Reporting Company
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		13,849,562

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 7,446	$ 8,000
Short-term investments	69,206	73,240
Prepaid expenses and other current assets	1,335	1,308
Total current assets	77,987	82,548
Restricted cash	132	132
Property and equipment, net	1,127	1,089
Intangible assets	1,453	1,453
Total assets	80,699	85,222
Current liabilities:
Accounts payable	528	193
Accrued liabilities	586	382
Deferred revenue	240	277
Deferred rent, current portion	66	48
Current portion of long-term debt	1,508	995
Total current liabilities	2,928	1,895
Deferred rent, long-term portion	67	66
Deferred tax liability	253	305
Long-term debt	3,570	4,039
Total liabilities	6,818	6,305
Commitments and contingencies
Convertible preferred stock, $0.001 par value per share; 10,000,000 shares authorized at March 31, 2018 and December 31, 2017; zero shares issued and outstanding at March 31, 2018 and December 31, 2017	0	0
Stockholders’ equity:
Common stock, $0.001 par value per share; 200,000,000 shares authorized at March 31, 2018 and December 31, 2017; 13,896,551 shares issued and 13,846,084 shares outstanding at March 31, 2018; 13,881,645 shares issued and 13,831,178 shares outstanding at December 31, 2017	14	14
Treasury stock, at cost; 50,467 shares at March 31, 2018 and December 31, 2017	0	0
Additional paid-in capital	88,864	88,346
Accumulated other comprehensive loss	(105)	(59)
Accumulated deficit	(14,892)	(9,384)
Total stockholders’ equity	73,881	78,917
Total liabilities, convertible preferred stock, and stockholders’ equity	$ 80,699	$ 85,222

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Convertible preferred stock, shares issued (in shares)	0	0
Convertible 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)	200,000,000	200,000,000
Common stock, shares issued (in shares)	13,896,551	13,881,645
Common stock, shares outstanding (in shares)	13,846,084	13,831,178
Treasury stock, shares (in shares)	50,467	50,467

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Collaboration revenue	$ 315	$ 737
Operating expenses:
Research and development	3,792	1,858
General and administrative	2,108	873
Total operating expenses	5,900	2,731
Loss from operations	(5,585)	(1,994)
Other income (expense):
Interest expense	(78)	0
Interest and other income	305	5
Loss before taxes	(5,358)	(1,989)
Income tax expense	52	0
Basic and diluted net loss attributable to common stockholders	(5,306)	(1,989)
Comprehensive loss:
Unrealized loss on investments	(46)	0
Comprehensive loss	$ (5,352)	$ (1,989)
Weighted-average shares used to compute basic and diluted net loss per share attributable to common stockholders (in shares)	13,844,731	615,844
Basic and diluted net loss per share attributable to common stockholders (in dollars per share)	$ (0.38)	$ (3.23)

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net loss	$ (5,306)	$ (1,989)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	80	46
Non-cash interest expense	44	0
Deferred income tax	(52)	0
Stock-based compensation and warrant expense	511	52
Changes in operating assets and liabilities:
Prepaid expenses	(27)	(134)
Accounts payable	335	199
Deferred revenue	(239)	(737)
Accrued liabilities	204	406
Deferred rent and other	19	(7)
Net cash used in operating activities	(4,431)	(2,164)
Investing activities
Purchases of property and equipment	(118)	(108)
Purchase of short-term investments	(37,037)	0
Proceeds from the sale of short-term investments	41,025	0
Accounts payable	3,870	(108)
Financing activities
Proceeds from sale of preferred stock	0	4,000
Proceeds from exercise of stock options and common stock warrants	7	21
Net cash provided by financing activities	7	4,021
Net (decrease) increase in cash and cash equivalents and restricted cash	(554)	1,749
Cash and cash equivalents and restricted cash, beginning of period	8,132	11,819
Cash and cash equivalents and restricted cash, end of period	7,578	13,568
Supplemental Information
Cash paid for interest	$ 34	$ 0

Description of the Business

Description of the Business	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of the Business Alpine Immune Sciences, Inc. (the “Company”, “Alpine”, “we”, “us”, or “our”) is focused on discovering and developing modern, protein-based immunotherapies targeting the immune synapse to treat cancer, inflammation, and other diseases. Our proprietary scientific platform uses a process known as directed evolution, or an iterative scientific engineering process purposefully conducted to “evolve” a protein to create therapeutics potentially capable of modulating immune system interactions. In our pre-clinical animal studies, our platform has proven capable of identifying novel molecules, including single domains capable of modulating multiple targets. We were incorporated under the laws of the State of Delaware and are headquartered in Seattle, Washington. Significant estimates inherent in the preparation of the accompanying condensed consolidated financial statements include recoverability and useful lives of intangible assets and the fair value of equity based awards. Rev erse Merger and Subscription Agreement On April 18, 2017, we entered into a merger agreement with Nivalis Therapeutics, Inc. (“Nivalis”), a public biotechnology company, and one of its wholly-owned subsidiaries pursuant to which, the subsidiary merged with and into Alpine, with Alpine continuing as a wholly owned subsidiary of Nivalis and the surviving corporation of the merger (the “Merger Agreement”). Nivalis Therapeutics, Inc. was incorporated in Delaware in March 2007. Alpine Immune Sciences, Inc. (prior to its business combination with Nivalis Therapeutics, Inc.) was incorporated in Delaware on December 30, 2014. The merger is intended to qualify for federal income tax purposes as a tax-free reorganization under the provisions of Section 368(a) of the Internal Revenue Code of 1986, as amended. At the closing of the merger, each outstanding share of our capital stock (common stock and preferred stock) was converted into the right to receive shares of Nivalis common stock (subject to the payment of cash in lieu of fractional shares and after giving effect to a 1:4 reverse stock split of Nivalis common stock) such that, immediately following the effective time of the merger, preexisting Nivalis stockholders, optionholders, and warrantholders owned, or held rights to acquire, approximately 26% of the fully-diluted common stock of Nivalis, which changed its name to “Alpine Immune Sciences, Inc.” following the completion of the merger and Alpine’s preexisting stockholders, optionholders, and warrantholders owned, or held rights to acquire approximately 74% of the fully-diluted common stock of Nivalis. The issuance of the shares to our pre-existing stockholders was registered under the Securities Act of 1933, as amended, pursuant to a registration statement on Form S-4 (No. 333-218134) (the “Registration Statement”) declared effective by the Securities and Exchange Commission (the “SEC”) on June 6, 2017. Contemporaneously with the execution and delivery of the Merger Agreement, certain of our pre-existing stockholders entered into a subscription agreement with us pursuant to which such stockholders purchased, immediately prior to the closing of the merger, 1,335,118 shares of our capital stock at a purchase price of $12.74 per share for an aggregate purchase price of approximately $17.0 million . The merger and the subscription described above were consummated on July 24, 2017 .

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Use of Estimates The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the SEC and generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements and accompanying notes. We base our estimates and assumptions on historical experience when available and on various factors we believe to be reasonable under the circumstances. Actual results could differ materially from those estimates. The results of our operations for the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the full year. Principles of Consolidation Our condensed consolidated financial statements include the financial position and results of operations of Alpine and AIS Operating Co., Inc., our wholly owned subsidiary and operating company. On July 24, 2017, we closed the merger on the terms described in more detail in Note 1. In connection with the merger, Nivalis effected a 1:4 reverse stock split of its common stock. Upon the closing of the merger, (1) a wholly-owned subsidiary of Nivalis merged with and into Alpine, with Alpine (renamed as “AIS Operating Co., Inc.”) remaining as the surviving entity; and (2) Nivalis was renamed as “Alpine Immune Sciences, Inc.” Unaudited Interim Financial Information The accompanying unaudited condensed consolidated financial statements as of March 31, 2018 , and for the three months ended March 31, 2018 and 2017 and the related interim information contained within the notes to the condensed consolidated financial statements are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and accompanying notes for the years December 31, 2017 and 2016 included in our Annual Report on Form 10-K for the year ended December 31, 2017, filed with the Securities and Exchange Commission ("SEC") on March 28, 2017 ("Annual Report"). Unless indicated otherwise, all amounts presented in financial tables are presented in thousands, except for share, per share and par value amounts. Restricted Cash Restricted cash represents cash drawn on a line of credit used to establish collateral to support the security deposit on our operating lease to rent office and laboratory space in Seattle, Washington. Short-Term Investments Our short-term investments include funds invested in highly liquid money market funds, U.S. Treasury securities, commercial paper, and corporate debt securities with a final maturity of each security of less than one year . All investments are classified as available-for-sale securities and are recorded at fair value based on quoted prices in active markets, with unrealized gains and losses excluded from earnings and reported in other comprehensive income (loss). Purchase premiums and discounts are recognized as interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value deemed to be other than temporary are reflected in the condensed consolidated statements of operations and comprehensive income (loss) using the specific-identification method. Revenue Recognition Revenue is recognized when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Our steps for recognizing revenue consist of; (1) identifying the contract, (2) identifying the performance obligations as either distinct or bundled goods and services, (3) determining the transaction price associated with each performance obligation for which we expect to be entitled in exchange for transferring such goods and services, (4) allocating the transaction price to the performance obligations in the contract and (5) recognizing revenue upon satisfaction of performance obligations. Our revenue is primarily derived from our License and Research Agreement (the “Collaboration Agreement”) with Kite Pharma, Inc. (“Kite”), which contains multiple performance obligations, which may include (1) grants of, or options to obtain, intellectual property licenses; (2) research and development services; and/or (3) manufacturing or supply services. Payments typically received under these arrangements include one or more of the following: non-refundable upfront license fees, option exercise fees, payment for research and/or development efforts, amounts due upon the achievement of specified objectives, and/or royalties on future product sales. We allocate revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling prices at the inception of the contract based on our best estimate of what the selling price would be if the deliverable was regularly sold by us on a stand-alone basis. Payments received prior to satisfying the relevant revenue recognition criteria are recorded as deferred revenue in the accompanying condensed consolidated balance sheets and recognized as revenue when the related revenue recognition criteria are met. We recognize revenue under the Collaboration Agreement based on employee hours contributed to each performance obligation. The Collaboration Agreement provides for non-refundable milestone payments. We recognize revenue that is contingent upon the achievement of a substantive milestone in its entirety in the period in which the milestone is achieved. A milestone is considered substantive when the consideration payable to us for such milestone (1) is consistent with our performance necessary to achieve the milestone or the increase in value to the collaboration resulting from our performance; (2) relates solely to our past performance; and (3) is reasonable relative to all of the other deliverables and payments within the arrangement. In making this assessment, we consider all facts and circumstances relevant to the arrangement, including factors such as the scientific, regulatory, commercial, and other risks that must be overcome to achieve the milestone, the level of effort and investment required to achieve the milestone and whether any portion of the milestone consideration is related to future performance or deliverables. We review the contributed employee hours for each performance obligation under the Collaboration Agreement, and adjust the revenue recognized to reflect changes in assumptions relating to the estimated satisfaction of the performance obligation. We could accelerate revenue recognition in the event of early termination of programs or if our expectations change. Alternatively, we could decelerate revenue recognition if programs are extended or delayed. While such changes to our estimates have no impact on our reported cash flows, the timing of revenue recorded in future periods could be materially impacted. Comprehensive Income (Loss) Comprehensive income (loss) is comprised of net income (loss) and certain changes in equity excluded from net income (loss). For the three months ended March 31, 2018 , other comprehensive loss consists of unrealized losses on our short-term investments. There was no difference between comprehensive income (loss) and net income (loss) for the three months ended March 31, 2017. Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases. ASU 2016-02 requires a lessee to separate the lease components from the non-lease components in a contract and recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. It also aligns lease accounting for lessors with the revenue recognition guidance in ASU 2014-09. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and is to be applied at the beginning of the earliest period presented using a modified retrospective approach. We are continuing to evaluate the effect the standard will have on our financial statements and related disclosures. Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, as amended ("new revenue standard" or "ASC 606"), which amends the guidance for revenue recognition to replace numerous industry specific requirements. ASC 606 implements a five-step process for customer contract revenue recognition focusing on transfer of control, as opposed to transfer of risk and rewards. ASC 606 also requires enhanced disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows from contracts with customers. Other major provisions include ensuring the time value of money is considered in the transaction price, and allowing estimates of variable consideration to be recognized before contingencies are resolved in certain circumstances. ASC 606 is effective for reporting periods beginning after December 15, 2017. On January 1, 2018, we adopted the new accounting standard and all of the related amendments using the modified retrospective method. We recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of our accumulated deficit. The cumulative effect of the changes related to the adoption of the new revenue standard and increased our beginning balances in accumulated deficit and deferred revenue by $203,000 within our condensed consolidated balance sheet. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. Our Collaboration Agreement with Kite is the only contract that impacted the adoption of the new revenue standard. Prior to the adoption of the new revenue standard, we recognized revenue under the Collaboration Agreement based upon the estimated performance periods related to the non-refundable upfront payments we received from Kite. Under the new standard, we recognize revenue based on employee hours contributed to each performance obligation. In accordance with the new revenue standard requirements, the disclosure of the impact of adoption on our condensed consolidated financial statements as of and for the three months ended March 31, 2018 is as follows (in thousands): As Reported Adjustments Balance without Adoption of ASC 606 Condensed Consolidated Balance Sheets Liabilities Deferred revenue $ 240 $ (91 ) $ 149 Stockholders’ equity Accumulated deficit (14,892 ) 91 (14,801 ) Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) Collaboration revenue $ 315 $ (112 ) $ 203 Net loss (5,306 ) (112 ) (5,418 ) In August 2016, the FASB issued ASU No. 2016-15 which provides new guidance on the classification of certain cash receipts and payments in the statement of cash flows. The new guidance is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. We adopted this new standard effective January 1, 2018. The adoption of this standard did not impact our financial statements. In May 2017, the FASB issued ASU No. 2017-09 to provide clarity and reduce both diversity in practice and cost and complexity when applying the guidance in Compensation - Stock Compensation (Topic 718) about a change to the terms and conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. The amendments in this update are effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, and applied prospectively to modifications occurring on or after the adoption date. We adopted this new standard effective January 1, 2018. The adoption of this standard did not have an impact on our financial statements. For the quarter ended March 31, 2018 , there were no modifications to the terms or conditions of a share-based payment award.

Business Combination

Business Combination	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Business Combination	Business Combination On July 24, 2017 , we closed the merger on the terms described in more detail in Note 1. In connection with the merger, Nivalis effected a 1:4 reverse stock split of its common stock. Upon the closing of the merger, (1) a wholly-owned subsidiary of Nivalis merged with and into Alpine, with Alpine (renamed as “AIS Operating Co., Inc.”) remaining as the surviving entity; and (2) Nivalis was renamed as “Alpine Immune Sciences, Inc.” Under the terms of the Merger Agreement, Nivalis issued shares of its common stock to Alpine’s stockholders, at an exchange rate of 0.4969 shares of Nivalis common stock, after taking into account the 1:4 reverse stock split, for each share of Alpine’s common stock and preferred stock outstanding immediately prior to the merger. The exchange rate was determined through arms-length negotiations between Nivalis and Alpine. Nivalis also assumed all of the stock options outstanding under Alpine’s Amended and Restated 2015 Stock Plan, as amended (the “Alpine Plan”), and stock warrants for Alpine’s capital stock outstanding immediately prior to the merger, with such stock options and warrants henceforth representing the right to purchase a number of shares of the Nivalis common stock equal to 0.4969 multiplied by the number of shares of Alpine’s common stock or preferred stock previously represented by such options and warrants. Nivalis also assumed the Alpine Plan. Immediately after the merger, there were 13,881,645 shares of common stock outstanding. Immediately after the merger, Alpine’s former stockholders, warrantholders, and optionholders owned, or held rights to acquire, approximately 74% of the fully-diluted common stock of Nivalis, which for these purposes is defined as the outstanding common stock of Nivalis, plus “in the money” options and warrants to purchase shares of Nivalis’ common stock, assuming all “in the money” options and warrants of Nivalis outstanding immediately prior to the merger are exercised on a cashless basis immediately prior to the closing of the merger, with Nivalis’ stockholders, optionholders, and warrantholders immediately prior to the merger owning, or holding rights to acquire, approximately 26% of the fully diluted common stock of Nivalis. More than 74% of Nivalis’ common stock outstanding immediately after the merger was held by stockholders party to lock-up agreements, pursuant to which such stockholders have agreed, except in limited circumstances, not to sell, transfer, or engage in swap or similar transactions with respect to shares of Nivalis’ common stock, including, as applicable, shares received in the merger and issuable upon exercise of certain warrants and options, for a period of 180 days following the completion of the merger. The issuance of shares of Nivalis’ common stock to our pre-existing stockholders was registered with the SEC pursuant to the Registration Statement. Immediately prior to the merger, we issued and sold an aggregate of approximately $17.0 million of shares of our capital stock to certain existing stockholders. For accounting purposes, our historical financial statements were not adjusted to reflect the merger, other than adjustments to the capital structure to reflect the historical capital structure of Nivalis. No other adjustments to our historical assets and liabilities were made as a result of the merger. In addition to the operating assets and liabilities of Nivalis, we also acquired Nivalis’ tax attributes, which primarily consisted of net operating losses which begin to expire in 2032 . Our ability to utilize the tax attributes of Nivalis may be limited under Section 382 of the U.S. Internal Revenue Service and as such, have been reserved. We recorded a deferred tax liability related to future tax benefits arising from in-process research and development ("IPR&D") acquired in the Merger. The combined organization is focusing on the development and commercialization of our innovative immunotherapies. Following the merger, the increased cash resources and increased access to capital of the combined organization will help to support the clinical development of our products. Consideration Transferred The fair value of the consideration transferred was based on the most reliable measure, which was determined to be the market price of Nivalis shares of common stock as of the acquisition date. The fair value of the consideration transferred consisted of the following (in thousands except share and per share amounts): Outstanding Nivalis common stock 3,914,058 Per share fair value of Nivalis common stock $ 9.60 Outstanding Nivalis stock options 421,992 Weighted average per share fair value of Nivalis stock options $ 1.25 Total fair value of consideration (in 000's) $ 38,103 Pursuant to the Merger Agreement, unvested Nivalis stock options immediately vested as of the closing of the business combination and were adjusted to give effect to the recapitalization. Purchase Price Allocation As Alpine was the accounting acquirer in the merger, we allocated the purchase price to the acquired tangible and intangible assets and assumed liabilities of Nivalis based on their estimated fair values as of the acquisition date. The excess of the estimated fair values of net assets acquired over the acquisition consideration paid was recorded as a bargain purchase gain in the condensed consolidated statements of operations and comprehensive income (loss). The determination of the preliminary fair values of the assets acquired and liabilities assumed requires significant judgment, including third party valuation estimates relating to the value of the acquired IPR&D. The allocation of the purchase consideration to the assets acquired and liabilities assumed in our financial statements was finalized as of December 31, 2017. Since the acquisition date, we have recorded adjustments to the allocation of the purchase consideration that included increases of $77,000 and $15,000 to other receivables and accrued liabilities, respectively, which resulted in a decrease of $62,000 in our bargain purchase gain. These purchase price adjustments are reflected in the accompanying consolidated balance sheet as of December 31, 2017. The final allocation of the purchase consideration is as follows (in thousands): Fair Value Assets: Cash and cash equivalents $ 31,130 Marketable securities 12,952 Other receivables 79 IPR&D 1,453 Total assets acquired 45,614 Liabilities: Accrued liabilities (401 ) Deferred tax liability (509 ) Total liabilities assumed (910 ) Bargain purchase gain (6,601 ) Total $ 38,103 We relied on significant Level 3 unobservable inputs to estimate the fair value of our acquired IPR&D using management’s estimate of future royalties and expected earnings of the assets after taking into account an estimate of future expenses necessary to bring the products to completion. These projected cash flows were then discounted to their present values using a discount rate of 17% , which was considered commensurate with the risks and stages of development of the IPR&D. The bargain purchase gain resulted from expenses incurred by Nivalis between the time the purchase price was negotiated and the close of the transaction, and changes in the Nivalis stock price during that period as the exchange ratio was fixed when the purchase price was negotiated. We recognized acquisition-related costs of $280,000 for the three months ended March 31, 2017. These costs are included within general and administrative expense in our condensed consolidated statements operations and of comprehensive income (loss). Pro Forma Financial Information The following pro forma consolidated results of net loss for the three months ended March 31, 2017 assume the business combination was completed as of January 1, 2017 (in thousands, except per share amounts): Three Months Ended Pro forma revenues $ 737 Pro forma net loss (10,494 ) Pro forma basic and diluted net loss per share $ (0.76 ) For purposes of the pro forma disclosures above, the primary adjustments for the three months ended March 31, 2018 include the elimination of acquisition related costs and acceleration of stock compensation expense upon the change in control. There was no difference in our pro forma financial information for the three months ended March 31, 2018 .

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share We compute net loss per share attributable to common stockholders using the two-class method required for participating securities. We consider our convertible preferred stock to be participating securities. In accordance with the two-class method, earnings allocated to these participating securities, which include participation rights in undistributed earnings, are subtracted from net income to determine total undistributed earnings to be allocated to common stockholders. Net loss is not allocated to participating securities as there is no contractual obligation to share in net losses. Basic net loss per share attributable to common stockholders is computed by dividing net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period. All participating securities are excluded from basic weighted-average common shares outstanding. Because of net losses recognized in each period, potential common shares issuable upon the exercise of outstanding stock options and warrants and the conversion of preferred shares into common shares have not been reflected in the calculation of diluted net loss per share due to the anti-dilutive effect. Diluted net loss per share, therefore, does not differ from basic net loss per share. The basic and diluted net loss per share for the three months ended March 31, 2018 was computed based on the weighted average shares of common stock outstanding during the respective periods. The net loss per share for the three months ended March 31, 2018 includes the conversion 9,301,433 shares of our convertible preferred stock into common stock, and 3,914,058 shares acquired in connection with the merger. The significant number of shares issued has affected the year-over-year comparability of our net loss per share calculations. The common stock issuable upon the conversion or exercise of the following dilutive securities has been excluded from the diluted net loss per share attributable to common stockholders calculation because their effect would have been anti-dilutive for the periods presented: March 31, 2018 2017 (unaudited) Convertible preferred stock — 5,019,000 Warrants to purchase common stock 24,123 — Options to purchase common stock 1,942,712 857,819 Total 1,966,835 5,876,819

Cash Equivalents and Short-Term

Cash Equivalents and Short-Term Investments	3 Months Ended
	Mar. 31, 2018
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash Equivalents and Short-term Investments	Cash Equivalents and Short-Term Investments The amortized cost and fair value of our cash equivalents and short-term investments are as follows (in thousands): March 31, 2018 Assets: (unaudited) Amortized Cost Gross unrealized gains Gross unrealized losses Fair market value Money market funds $ 5,955 $ — $ — $ 5,955 U.S. treasury bills 14,367 — (26 ) 14,341 Corporate debt securities and commercial paper 54,944 — (79 ) 54,865 Total $ 75,266 $ — $ (105 ) $ 75,161 December 31, 2017 Assets: Amortized Cost Gross unrealized gains Gross unrealized losses Fair market value Money market funds $ 5,680 $ — $ — $ 5,680 U.S. treasury bills 19,909 — (21 ) 19,888 Corporate debt securities and commercial paper 53,390 — (38 ) 53,352 Total $ 78,979 $ — $ (59 ) $ 78,920 All short-term investments held as of March 31, 2018 were classified as available-for-sale securities and had contractual maturities of less than one year . There were no realized gains and losses on these securities for the periods presented.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is defined as the exchange price received for an asset or paid to transfer a liability, or an exit price, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, is as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 : Unobservable inputs supported by little or no market activity and significant to the fair value of the assets or liabilities. As of March 31, 2018 and December 31, 2017, cash of $1.5 million and $2.3 million , respectively, is excluded from the following fair value table below. The following table summarizes our financial assets and liabilities measured at fair value on a recurring basis (in thousands): March 31, 2018 (unaudited) Assets: Level 1 Level 2 Level 3 Total Money market funds $ 5,955 $ — $ — $ 5,955 U.S. treasury bills 14,341 — — 14,341 Corporate debt securities and commercial paper — 54,865 — 54,865 Total $ 20,296 $ 54,865 $ — $ 75,161 December 31, 2017 Assets: Level 1 Level 2 Level 3 Total Money market funds $ 5,680 $ — $ — $ 5,680 U.S. treasury bills 19,888 — — 19,888 Corporate debt securities and commercial paper — 53,352 — 53,352 Total $ 25,568 $ 53,352 $ — $ 78,920 Our Level 2 assets consist of commercial paper and corporate debt securities. We review trading activity and pricing for our available-for-sale securities as of the measurement date. When sufficient quoted pricing for identical securities is not available, we use market pricing and other observable market inputs for similar securities obtained from various third-party data providers. These inputs either represent quoted prices for similar assets in active markets or have been derived from observable market data.

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2018
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, 2018 December 31, 2017 (unaudited) Accrued research and development $ 95 $ 197 Accrued professional fees 395 112 Accrued taxes and licenses 17 30 Accrued other 79 43 Total $ 586 $ 382

Long-term Debt

Long-term Debt	3 Months Ended
	Mar. 31, 2018
Debt Instruments [Abstract]
Long-term Debt	Long-term Debt On June 30, 2017, we drew down a term loan of $5.0 million from Silicon Valley Bank with whom we had entered into a long-term financing arrangement on December 16, 2016. The loan has an interest-only period that expires on July 1, 2018 , at which point we will be obligated to make thirty consecutive equal monthly payments of principal (each in an amount that will fully amortize the loan), plus accrued interest. Interest accrues at a floating per annum rate equal to the lender’s prime rate minus 1.75% . As a condition to the loan, we agreed to pay a final payment fee of 7.5% , or $375,000 , upon repayment of the loan. The final payment fee was recorded in long-term debt with an offsetting reduction in long-term debt and was accounted for as a debt discount. Pursuant to the loan agreement we have pledged substantially all of our assets, excluding intellectual property, as collateral. The obligations under the loan agreement are subject to acceleration upon the occurrence of specified events of default, including a material adverse change in our business, operations, financial, or other condition. We assessed the likelihood of the lender accelerating payment of the loan due to a material adverse change in our business, operations, financial, or other condition as remote. As such, as of March 31, 2018 , the classification of the loan is split between current and noncurrent based on the timing of payment obligations. The term loan agreement contains customary conditions to borrowings, events of default and negative covenants, including covenants that could limit our ability to, among other things, incur additional indebtedness, liens or other encumbrances; make dividends or other distributions; buy, sell or transfer assets; engage in any new line of business; and enter into certain transactions with affiliates. We were in compliance with our covenants as of March 31, 2018 . Also, in connection with the drawdown of the loan, we also granted the financial institution 7,069 Series A -1 Preferred Stock warrants at an exercise price of $12.38 per share. The fair value of the warrants on the date of issuance was $53,000 , determined using the Black-Scholes option-pricing model, and was recorded as a discount to the note and as a warrant liability on the accompanying condensed consolidated balance sheets. In connection with the merger and conversion of all outstanding Series A-1 preferred stock, the warrants became exercisable for 7,069 fully vested shares of our common stock. As a result of the change in the underlying shares, the warrants were equity-classified beginning on July 24, 2017 . The debt discount is being amortized to interest expense using the effective interest method over the repayment term of the initial loan amount. Non-cash interest expense associated with the amortization of the discount was $44,000 for the three months ended March 31, 2018 . The unamortized discount was $298,000 as of March 31, 2018 .

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Lease We lease laboratory and office space under an operating lease in Seattle, Washington. In January 2018, we entered into a lease amendment for approximately 6,184 square feet of additional office and laboratory space adjacent to our existing leased premises. The lease expires on December 31, 2019 and has two options to extend the lease term with each option enabling us to extend the lease term by twelve months. The annual base rent due under the amendment is $295,000 for the first year and will increase by 3.0% each year thereafter.

License and Collaboration Agree

License and Collaboration Agreement	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Collaboration Agreement	License and Collaboration Agreement In October 2015, we entered into a Collaboration and Licensing Agreement with Kite Pharma, Inc. to discover and develop protein-based immunotherapies targeting the immune synapse to treat cancer. Under our agreement, we are to perform certain research services and grant to Kite an exclusive license to two programs from our transmembrane immunomodulatory protein (TIP™) technology, which Kite is planning to further engineer into chimeric antigen receptor (“CAR”) and T cell receptor (“TCR”) product candidates. Under the terms of the Collaboration Agreement, Kite made upfront payments to us of $5.5 million , which were initially recorded as deferred revenue. As of March 31, 2018 , we are eligible to receive milestone payments based upon the successful achievement of pre-specified research, clinical, and regulatory milestones totaling up to $530.0 million plus royalty payments on product sales, if any. Kite will receive an exclusive, worldwide license to research, develop, and commercialize engineered autologous T cell therapies incorporating two programs coming from our platform. In October 2017, we entered into an amendment with Kite to extend the research term of the Collaboration Agreement. Under the amended agreement, we are eligible to receive an additional $450,000 in research support payments from Kite in two tranches (instead of a single tranche as previously contemplated by the original Collaboration Agreement) (the “Amendment”). We recorded revenue of $240,000 and $737,000 for the three months ended March 31, 2018 and 2017 , respectively. On January 1, 2018, we adopted the new revenue standard using the modified retrospective method. We recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of our accumulated deficit. The cumulative effect of the changes related to the adoption of the new revenue standard increased our beginning balances in accumulated deficit and deferred revenue by $203,000 within our condensed consolidated balance sheet. Prior to the adoption of the new revenue standard, we recognized revenue under the Collaboration Agreement based upon the estimated performance periods related to the non-refundable upfront payments we received from Kite. Under the new standard, we recognize revenue based on employee hours contributed to each performance obligation. We recognized $112,000 in higher revenue for the three months ended March 31, 2018 , as compared to what would have been recorded under previous accounting guidance.

Stockholders' Deficit

Stockholders' Deficit	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity Note [Abstract]
Stockholders’ Deficit	Stockholders’ Deficit Stock-Based Compensation Expense We use the Black-Scholes option pricing model to estimate the fair value of stock options granted to employees at the grant date. We recognize the fair value of stock-based compensation as compensation expense over the requisite service period, which is the vesting period. We also record stock options and other stock-based compensation issued to non-employees at fair value as of the date of grant using the Black-Scholes option pricing model. Non-employee awards are remeasured to reflect the current fair value at each reporting period and expense is recognized over the related vesting period. Assumptions used in valuing non-employee stock options are generally consistent with those used for employee stock options with the exception that the expected term is over the contractual life. Stock-based compensation and warrant expense is classified in the condensed consolidated statements of operations and comprehensive income (loss) as follows (in thousands): Three Months Ended 2018 2017 (unaudited) Employee: Research and development $ 197 $ 13 General and administrative 308 27 Non-Employee: Research and development 1 12 General and administrative 5 — Total stock-based compensation expense $ 511 $ 52

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes In December 2017, the SEC issued Staff Accounting Bulletin (SAB) 118 to address the application of U.S. GAAP in situations in which a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act (the Tax Reform Act) which was signed into law on December 22, 2017. In March 2018, the FASB issued ASU 2018-05, which amended ASC 740 to incorporate the requirements of SAB 118. We recognized the provisional tax impacts of the Tax Reform Act in the fourth quarter of 2017. During the first quarter of 2018, we did not receive any additional information regarding these provisional calculations, except as disclosed in this footnote. As a result, we continue to anticipate finalizing our analysis in connection with the completion of our tax return for 2017 to be filed in 2018. We are subject to income taxes in the United States and our effective tax rate is calculated quarterly based upon current assumptions relating to the full year’s estimated operating results and various tax-related items. Our effective tax rate for the three -month period ended March 31, 2018 was 0.98% . The difference between the effective tax rate of 0.98% and the U.S. federal statutory rate of 21% for the three -month period ended March 31, 2018 was primarily due to recognizing a full valuation allowance on deferred tax assets. As of March 31, 2018 , we determined that, based on all available evidence, both positive and negative, including our latest forecasts and cumulative losses in recent years, it was more likely than not that none of our deferred tax assets would be realized and therefore we continued to record a full valuation allowance. No current tax liability or expense has been recorded in the financial statements. As part of the merger, we identified $1.5 million of acquired IPR&D. IPR&D acquired in a business combination is an indefinite-lived intangible asset until the completion or abandonment of the associated R&D efforts. Once the research and development efforts are completed or abandoned, the IPR&D will either be impaired or amortized over the asset life as a finite-lived intangible. As the acquired IPR&D is not completed, and has not been abandoned, it is considered indefinite-lived for accounting purposes. Any future reversal of a deferred tax liability resulting from IPR&D costs cannot be scheduled for tax purposes and therefore cannot be considered as a source of future taxable income. Thus, as of December 31, 2017 , we had recorded a deferred tax liability of $305,000 as a result of the acquired IPR&D having a financial reporting basis of $1.5 million and a tax basis of $0 . However, we are projecting a large NOL for the 2018 tax year, and under the newly reformed U.S. corporate income tax laws, federal NOLs incurred during 2018 are carried forward indefinitely. As such, the indefinite nature of the estimated 2018 NOL is such that it can be scheduled against the indefinite lived intangible, thus eliminating the need to record a deferred tax liability outside of the valuation allowance. Accordingly, we have calculated an annual estimated tax rate of 0.98% , which represents the estimated annual benefit of the removal of the deferred tax liability, and have applied the rate to the quarterly results from continuing operations, arriving at a tax benefit for the quarter of $52,000 . Current tax laws impose substantial restrictions on the utilization of R&D credit and net operating loss carryforwards in the event of an ownership change, as defined by the Internal Revenue Code Section 382 and 383. Such an event may limit our ability to utilize net operating losses and R&D tax credit carryforwards. Under Internal Revenue Code Section 382 and 383, the third quarter 2017 merger with Nivalis Therapeutics is likely considered an ownership change with respect to the potential limitation of the Nivalis Therapeutics federal tax credits and net operating losses. As such, it is likely that any future utilization of Nivalis Therapeutics federal tax credits and net operating losses is substantially limited. Therefore, all Nivalis Therapeutics tax credit and net operating loss carryforwards have been reduced to $0 . Our net operating loss carry forward amounts expire starting in 2037 , while our federal research and development tax credit carry forward amounts expire starting in 2035. As of December 31, 2017 , we had accumulated approximately $12.0 million of federal tax losses and $0 (tax effected) of state tax losses, and $600,000 in federal research and development tax credits. Due to our operating loss carryforwards, all tax years remain open to examination by the major taxing jurisdictions to which we are subject. In the event we are assessed interest or penalties at some point in the future, it will be classified in the financial statements as tax expense. Under ASC 740, the benefit of an uncertain tax position that is more likely than not of being sustained upon audit by the relevant taxing authority must be recognized at the largest amount that is more likely than not to be sustained. No portion of the benefit of an uncertain tax position may be recognized if the position has less than a 50% likelihood of being sustained. We have an uncertain tax position on our research and development credits as of the three month period ended March 31, 2018 . However, no deferred asset is recorded for the credits due to the full valuation allowance.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the SEC and generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements and accompanying notes. We base our estimates and assumptions on historical experience when available and on various factors we believe to be reasonable under the circumstances. Actual results could differ materially from those estimates. The results of our operations for the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the full year.
Principles of Consolidation	Principles of Consolidation Our condensed consolidated financial statements include the financial position and results of operations of Alpine and AIS Operating Co., Inc., our wholly owned subsidiary and operating company. On July 24, 2017, we closed the merger on the terms described in more detail in Note 1. In connection with the merger, Nivalis effected a 1:4 reverse stock split of its common stock. Upon the closing of the merger, (1) a wholly-owned subsidiary of Nivalis merged with and into Alpine, with Alpine (renamed as “AIS Operating Co., Inc.”) remaining as the surviving entity; and (2) Nivalis was renamed as “Alpine Immune Sciences, Inc.”
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying unaudited condensed consolidated financial statements as of March 31, 2018 , and for the three months ended March 31, 2018 and 2017 and the related interim information contained within the notes to the condensed consolidated financial statements are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and accompanying notes for the years December 31, 2017 and 2016 included in our Annual Report on Form 10-K for the year ended December 31, 2017, filed with the Securities and Exchange Commission ("SEC") on March 28, 2017 ("Annual Report"). Unless indicated otherwise, all amounts presented in financial tables are presented in thousands, except for share, per share and par value amounts.
Short-Term Investments	Short-Term Investments Our short-term investments include funds invested in highly liquid money market funds, U.S. Treasury securities, commercial paper, and corporate debt securities with a final maturity of each security of less than one year . All investments are classified as available-for-sale securities and are recorded at fair value based on quoted prices in active markets, with unrealized gains and losses excluded from earnings and reported in other comprehensive income (loss). Purchase premiums and discounts are recognized as interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value deemed to be other than temporary are reflected in the condensed consolidated statements of operations and comprehensive income (loss) using the specific-identification method.
Revenue Recognition	Revenue Recognition Revenue is recognized when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Our steps for recognizing revenue consist of; (1) identifying the contract, (2) identifying the performance obligations as either distinct or bundled goods and services, (3) determining the transaction price associated with each performance obligation for which we expect to be entitled in exchange for transferring such goods and services, (4) allocating the transaction price to the performance obligations in the contract and (5) recognizing revenue upon satisfaction of performance obligations. Our revenue is primarily derived from our License and Research Agreement (the “Collaboration Agreement”) with Kite Pharma, Inc. (“Kite”), which contains multiple performance obligations, which may include (1) grants of, or options to obtain, intellectual property licenses; (2) research and development services; and/or (3) manufacturing or supply services. Payments typically received under these arrangements include one or more of the following: non-refundable upfront license fees, option exercise fees, payment for research and/or development efforts, amounts due upon the achievement of specified objectives, and/or royalties on future product sales. We allocate revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling prices at the inception of the contract based on our best estimate of what the selling price would be if the deliverable was regularly sold by us on a stand-alone basis. Payments received prior to satisfying the relevant revenue recognition criteria are recorded as deferred revenue in the accompanying condensed consolidated balance sheets and recognized as revenue when the related revenue recognition criteria are met. We recognize revenue under the Collaboration Agreement based on employee hours contributed to each performance obligation. The Collaboration Agreement provides for non-refundable milestone payments. We recognize revenue that is contingent upon the achievement of a substantive milestone in its entirety in the period in which the milestone is achieved. A milestone is considered substantive when the consideration payable to us for such milestone (1) is consistent with our performance necessary to achieve the milestone or the increase in value to the collaboration resulting from our performance; (2) relates solely to our past performance; and (3) is reasonable relative to all of the other deliverables and payments within the arrangement. In making this assessment, we consider all facts and circumstances relevant to the arrangement, including factors such as the scientific, regulatory, commercial, and other risks that must be overcome to achieve the milestone, the level of effort and investment required to achieve the milestone and whether any portion of the milestone consideration is related to future performance or deliverables. We review the contributed employee hours for each performance obligation under the Collaboration Agreement, and adjust the revenue recognized to reflect changes in assumptions relating to the estimated satisfaction of the performance obligation. We could accelerate revenue recognition in the event of early termination of programs or if our expectations change. Alternatively, we could decelerate revenue recognition if programs are extended or delayed. While such changes to our estimates have no impact on our reported cash flows, the timing of revenue recorded in future periods could be materially impacted.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) is comprised of net income (loss) and certain changes in equity excluded from net income (loss). For the three months ended March 31, 2018 , other comprehensive loss consists of unrealized losses on our short-term investments.
Recently Issued and Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases. ASU 2016-02 requires a lessee to separate the lease components from the non-lease components in a contract and recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. It also aligns lease accounting for lessors with the revenue recognition guidance in ASU 2014-09. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and is to be applied at the beginning of the earliest period presented using a modified retrospective approach. We are continuing to evaluate the effect the standard will have on our financial statements and related disclosures. Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, as amended ("new revenue standard" or "ASC 606"), which amends the guidance for revenue recognition to replace numerous industry specific requirements. ASC 606 implements a five-step process for customer contract revenue recognition focusing on transfer of control, as opposed to transfer of risk and rewards. ASC 606 also requires enhanced disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows from contracts with customers. Other major provisions include ensuring the time value of money is considered in the transaction price, and allowing estimates of variable consideration to be recognized before contingencies are resolved in certain circumstances. ASC 606 is effective for reporting periods beginning after December 15, 2017. On January 1, 2018, we adopted the new accounting standard and all of the related amendments using the modified retrospective method. We recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of our accumulated deficit. The cumulative effect of the changes related to the adoption of the new revenue standard and increased our beginning balances in accumulated deficit and deferred revenue by $203,000 within our condensed consolidated balance sheet. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. Our Collaboration Agreement with Kite is the only contract that impacted the adoption of the new revenue standard. Prior to the adoption of the new revenue standard, we recognized revenue under the Collaboration Agreement based upon the estimated performance periods related to the non-refundable upfront payments we received from Kite. Under the new standard, we recognize revenue based on employee hours contributed to each performance obligation. In accordance with the new revenue standard requirements, the disclosure of the impact of adoption on our condensed consolidated financial statements as of and for the three months ended March 31, 2018 is as follows (in thousands): As Reported Adjustments Balance without Adoption of ASC 606 Condensed Consolidated Balance Sheets Liabilities Deferred revenue $ 240 $ (91 ) $ 149 Stockholders’ equity Accumulated deficit (14,892 ) 91 (14,801 ) Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) Collaboration revenue $ 315 $ (112 ) $ 203 Net loss (5,306 ) (112 ) (5,418 ) In August 2016, the FASB issued ASU No. 2016-15 which provides new guidance on the classification of certain cash receipts and payments in the statement of cash flows. The new guidance is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. We adopted this new standard effective January 1, 2018. The adoption of this standard did not impact our financial statements. In May 2017, the FASB issued ASU No. 2017-09 to provide clarity and reduce both diversity in practice and cost and complexity when applying the guidance in Compensation - Stock Compensation (Topic 718) about a change to the terms and conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. The amendments in this update are effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, and applied prospectively to modifications occurring on or after the adoption date. We adopted this new standard effective January 1, 2018. The adoption of this standard did not have an impact on our financial statements. For the quarter ended March 31, 2018 , there were no modifications to the terms or conditions of a share-based payment award.
Net Loss Per Share	Net Loss Per Share We compute net loss per share attributable to common stockholders using the two-class method required for participating securities. We consider our convertible preferred stock to be participating securities. In accordance with the two-class method, earnings allocated to these participating securities, which include participation rights in undistributed earnings, are subtracted from net income to determine total undistributed earnings to be allocated to common stockholders. Net loss is not allocated to participating securities as there is no contractual obligation to share in net losses. Basic net loss per share attributable to common stockholders is computed by dividing net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period. All participating securities are excluded from basic weighted-average common shares outstanding. Because of net losses recognized in each period, potential common shares issuable upon the exercise of outstanding stock options and warrants and the conversion of preferred shares into common shares have not been reflected in the calculation of diluted net loss per share due to the anti-dilutive effect. Diluted net loss per share, therefore, does not differ from basic net loss per share.
Fair Value Measurements	Fair Value Measurements Fair value is defined as the exchange price received for an asset or paid to transfer a liability, or an exit price, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, is as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 : Unobservable inputs supported by little or no market activity and significant to the fair value of the assets or liabilities.
Stock-Based Compensation Expense	Stock-Based Compensation Expense We use the Black-Scholes option pricing model to estimate the fair value of stock options granted to employees at the grant date. We recognize the fair value of stock-based compensation as compensation expense over the requisite service period, which is the vesting period. We also record stock options and other stock-based compensation issued to non-employees at fair value as of the date of grant using the Black-Scholes option pricing model. Non-employee awards are remeasured to reflect the current fair value at each reporting period and expense is recognized over the related vesting period. Assumptions used in valuing non-employee stock options are generally consistent with those used for employee stock options with the exception that the expected term is over the contractual life.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	In accordance with the new revenue standard requirements, the disclosure of the impact of adoption on our condensed consolidated financial statements as of and for the three months ended March 31, 2018 is as follows (in thousands): As Reported Adjustments Balance without Adoption of ASC 606 Condensed Consolidated Balance Sheets Liabilities Deferred revenue $ 240 $ (91 ) $ 149 Stockholders’ equity Accumulated deficit (14,892 ) 91 (14,801 ) Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) Collaboration revenue $ 315 $ (112 ) $ 203 Net loss (5,306 ) (112 ) (5,418 )

Business Combination (Tables)

Business Combination (Tables) - Nivalis Therapeutics, Inc.	3 Months Ended
	Mar. 31, 2018
Business Acquisition [Line Items]
Schedule of Fair Value of Consideration Transferred	The fair value of the consideration transferred consisted of the following (in thousands except share and per share amounts): Outstanding Nivalis common stock 3,914,058 Per share fair value of Nivalis common stock $ 9.60 Outstanding Nivalis stock options 421,992 Weighted average per share fair value of Nivalis stock options $ 1.25 Total fair value of consideration (in 000's) $ 38,103
Schedule of Initial Allocation of Purchase Consideration	The final allocation of the purchase consideration is as follows (in thousands): Fair Value Assets: Cash and cash equivalents $ 31,130 Marketable securities 12,952 Other receivables 79 IPR&D 1,453 Total assets acquired 45,614 Liabilities: Accrued liabilities (401 ) Deferred tax liability (509 ) Total liabilities assumed (910 ) Bargain purchase gain (6,601 ) Total $ 38,103
Schedule of Pro Forma Financial Information	The following pro forma consolidated results of net loss for the three months ended March 31, 2017 assume the business combination was completed as of January 1, 2017 (in thousands, except per share amounts): Three Months Ended Pro forma revenues $ 737 Pro forma net loss (10,494 ) Pro forma basic and diluted net loss per share $ (0.76 )

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Anti-dilutive Securities Excluded from Diluted Net Loss Per Share Attributable to Common Stockholders Calculation	The common stock issuable upon the conversion or exercise of the following dilutive securities has been excluded from the diluted net loss per share attributable to common stockholders calculation because their effect would have been anti-dilutive for the periods presented: March 31, 2018 2017 (unaudited) Convertible preferred stock — 5,019,000 Warrants to purchase common stock 24,123 — Options to purchase common stock 1,942,712 857,819 Total 1,966,835 5,876,819

Cash Equivalents and Short-Te22

Cash Equivalents and Short-Term Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Summary of Amortized Cost and Fair Value of Cash Equivalents and Short Term Investments	The amortized cost and fair value of our cash equivalents and short-term investments are as follows (in thousands): March 31, 2018 Assets: (unaudited) Amortized Cost Gross unrealized gains Gross unrealized losses Fair market value Money market funds $ 5,955 $ — $ — $ 5,955 U.S. treasury bills 14,367 — (26 ) 14,341 Corporate debt securities and commercial paper 54,944 — (79 ) 54,865 Total $ 75,266 $ — $ (105 ) $ 75,161 December 31, 2017 Assets: Amortized Cost Gross unrealized gains Gross unrealized losses Fair market value Money market funds $ 5,680 $ — $ — $ 5,680 U.S. treasury bills 19,909 — (21 ) 19,888 Corporate debt securities and commercial paper 53,390 — (38 ) 53,352 Total $ 78,979 $ — $ (59 ) $ 78,920

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes our financial assets and liabilities measured at fair value on a recurring basis (in thousands): March 31, 2018 (unaudited) Assets: Level 1 Level 2 Level 3 Total Money market funds $ 5,955 $ — $ — $ 5,955 U.S. treasury bills 14,341 — — 14,341 Corporate debt securities and commercial paper — 54,865 — 54,865 Total $ 20,296 $ 54,865 $ — $ 75,161 December 31, 2017 Assets: Level 1 Level 2 Level 3 Total Money market funds $ 5,680 $ — $ — $ 5,680 U.S. treasury bills 19,888 — — 19,888 Corporate debt securities and commercial paper — 53,352 — 53,352 Total $ 25,568 $ 53,352 $ — $ 78,920

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, 2018 December 31, 2017 (unaudited) Accrued research and development $ 95 $ 197 Accrued professional fees 395 112 Accrued taxes and licenses 17 30 Accrued other 79 43 Total $ 586 $ 382

Stockholders' Deficit (Tables)

Stockholders' Deficit (Tables)	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity Note [Abstract]
Schedule of Stock-based Compensation Expense	Stock-based compensation and warrant expense is classified in the condensed consolidated statements of operations and comprehensive income (loss) as follows (in thousands): Three Months Ended 2018 2017 (unaudited) Employee: Research and development $ 197 $ 13 General and administrative 308 27 Non-Employee: Research and development 1 12 General and administrative 5 — Total stock-based compensation expense $ 511 $ 52

Description of the Business - A

Description of the Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 24, 2017	Jul. 24, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Description Of Business [Line Items]
Convertible preferred stock, shares issued (in shares)			0		0
Convertible preferred stock, par value (in dollars per share)			$ 0.001		$ 0.001
Aggregate purchase price			$ 0	$ 4,000
Convertible preferred stock
Description Of Business [Line Items]
Convertible preferred stock, shares issued (in shares)	1,335,118	1,335,118
Convertible preferred stock, par value (in dollars per share)	$ 12.74	$ 12.74
Aggregate purchase price	$ 17,000	$ 17,000
Nivalis Therapeutics, Inc.
Description Of Business [Line Items]
Stock split conversion ratio	0.25
Expected ownership percentage immediately following merger consummation	26.00%	26.00%
Alpine’s Preexisting Stockholders, Optionholders, and Warrantholders
Description Of Business [Line Items]
Expected ownership percentage immediately following merger consummation	74.00%

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Additional Information (Details)	Jul. 24, 2017	Mar. 31, 2018USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)
Significant Accounting Policies
Available for sale securities, contractual maturity period (less than)		1 year
Accumulated deficit		$ (14,892,000)		$ (9,384,000)
Deferred revenue		$ 240,000		$ 277,000
Maximum
Significant Accounting Policies
Available for sale securities, contractual maturity period (less than)		1 year
Nivalis Therapeutics, Inc.
Significant Accounting Policies
Stock split conversion ratio	0.25
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Significant Accounting Policies
Accumulated deficit		$ 91,000	$ 203,000
Deferred revenue			$ 203,000

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Schedule of New Accounting Pronouncements (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
Stockholders’ equity
Accumulated deficit	$ (14,892,000)			$ (9,384,000)
Condensed Consolidated Statements of Operations and Comprehensive Income (Loss)
Collaboration revenue	315,000	$ 737,000
Net loss	(5,306,000)	$ (1,989,000)
As Reported
Liabilities
Deferred revenue	240,000
Stockholders’ equity
Accumulated deficit	(14,892,000)
Condensed Consolidated Statements of Operations and Comprehensive Income (Loss)
Collaboration revenue	315,000
Net loss	(5,306,000)
Balance without Adoption of ASC 606
Liabilities
Deferred revenue	149,000
Stockholders’ equity
Accumulated deficit	(14,801,000)
Condensed Consolidated Statements of Operations and Comprehensive Income (Loss)
Collaboration revenue	203,000
Net loss	(5,418,000)
Accounting Standards Update 2014-09 | Adjustments
Liabilities
Deferred revenue	(91,000)
Stockholders’ equity
Accumulated deficit	91,000		$ 203,000
Condensed Consolidated Statements of Operations and Comprehensive Income (Loss)
Collaboration revenue	(112,000)
Net loss	$ (112,000)

Business Combination - Addition

Business Combination - Additional Information (Details) - USD ($) $ in Thousands	Jul. 24, 2017	Jul. 24, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Jul. 25, 2017
Business Acquisition [Line Items]
Common stock, shares outstanding (in shares)			13,846,084		13,831,178	13,881,645
Percentage of shares outstanding after merger		74.00%
Aggregate purchase price			$ 0	$ 4,000
Percenatge of projected cash flows discounted to their present value using discount rate			17.00%
Acquisition-related costs				$ 280
Convertible preferred stock
Business Acquisition [Line Items]
Aggregate purchase price	$ 17,000	$ 17,000
Common Stock
Business Acquisition [Line Items]
Lock out period of shares issued in merger			180 days
Alpine’s Preexisting Stockholders, Optionholders, and Warrantholders
Business Acquisition [Line Items]
Ownership percentage immediately following effective merger consummation	74.00%
Expected ownership percentage immediately following merger consummation	74.00%
Alpine’s Preexisting Stockholders, Optionholders, and Warrantholders | Common Stock
Business Acquisition [Line Items]
Stock split conversion ratio		0.4969
Nivalis Therapeutics, Inc.
Business Acquisition [Line Items]
Stock split conversion ratio	0.25
Common stock, shares outstanding (in shares)	3,914,058	3,914,058
Expected ownership percentage immediately following merger consummation	26.00%	26.00%
Adjustments to the allocation of the purchase consideration included in increase in other receivables					$ 77
Adjustments to the allocation of the purchase consideration included in increase in accrued liabilities					15
Adjustments to the allocation of the purchase consideration included in increase in bargain purchase gain					$ 62

Business Combination - Schedule

Business Combination - Schedule of Fair Value of Consideration Transferred (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 24, 2017	Jul. 24, 2017	Mar. 31, 2018	Dec. 31, 2017	Jul. 25, 2017
Business Acquisition [Line Items]
Outstanding Nivalis common stock (in shares)			13,846,084	13,831,178	13,881,645
Nivalis Therapeutics, Inc.
Business Acquisition [Line Items]
Outstanding Nivalis common stock (in shares)	3,914,058	3,914,058
Per share fair value of Nivalis common stock (in dollars per share)	$ 9.60	$ 9.60
Outstanding Nivalis stock options (in shares)	421,992	421,992
Weighted average per share fair value of Nivalis stock options (in dollars per share)	$ 1.25	$ 1.25
Total fair value of consideration (in 000's)	$ 38,103	$ 38,103

Business Combination - Schedu31

Business Combination - Schedule of Initial Allocation of Purchase Consideration (Detail) - USD ($) $ in Thousands	Jul. 24, 2017	Jul. 24, 2017	Dec. 31, 2017
Assets:
IPR&D	$ 1,500	$ 1,500
Nivalis Therapeutics, Inc.
Assets:
Cash and cash equivalents	31,130	31,130
Marketable securities	12,952	12,952
Other receivables	79	79
IPR&D	1,453	1,453
Total assets acquired	45,614	45,614
Liabilities:
Accrued liabilities	(401)	(401)
Deferred tax liability	(509)	(509)	$ (305)
Total liabilities assumed	(910)	(910)
Bargain purchase gain		(6,601)
Total	$ 38,103	$ 38,103

Business Combination - Schedu32

Business Combination - Schedule of Pro Forma Financial Information (Details) - Nivalis Therapeutics, Inc. $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)$ / shares
Business Acquisition [Line Items]
Pro forma revenues	$ 737
Pro forma net loss	$ (10,494)
Pro forma basic and diluted net loss per share (in dollars per share) | $ / shares	$ (0.76)

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Details) - Common Stock	Jul. 24, 2017shares
Earnings Per Share [Line Items]
Convertible preferred stock (in shares)	9,301,433
Shares acquired in connection with merger (in shares)	3,914,058

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Anti-dilutive Securities Excluded from Diluted Net Loss Per Share Attributable to Common Stockholders Calculation (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,966,835	5,876,819
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0	5,019,000
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	24,123	0
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,942,712	857,819

Cash Equivalents and Short-Te35

Cash Equivalents and Short-Term Investments - Summary of Amortized Cost and Fair Value of CashEquivalents and Short Term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 75,266	$ 78,979
Gross unrealized gains	0	0
Gross unrealized losses	(105)	(59)
Fair market value	75,161	78,920
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,955	5,680
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair market value	5,955	5,680
U.S. treasury bills
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,367	19,909
Gross unrealized gains	0	0
Gross unrealized losses	(26)	(21)
Fair market value	14,341	19,888
Corporate debt securities and commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	54,944	53,390
Gross unrealized gains	0	0
Gross unrealized losses	(79)	(38)
Fair market value	$ 54,865	$ 53,352

Cash Equivalents and Short-Te36

Cash Equivalents and Short-Term Investments - Additional Information (Details)	3 Months Ended
	Mar. 31, 2018USD ($)
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Available for sale securities, contractual maturity period (less than)	1 year
Realized gains (losses) on securities	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Cash	$ 1.5	$ 2.3

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	$ 75,161	$ 78,920
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	5,955	5,680
Corporate debt securities and commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	54,865	53,352
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	75,161	78,920
Fair Value, Measurements, Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	5,955	5,680
Fair Value, Measurements, Recurring | U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	14,341	19,888
Fair Value, Measurements, Recurring | Corporate debt securities and commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	54,865	53,352
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	20,296	25,568
Fair Value, Measurements, Recurring | Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	5,955	5,680
Fair Value, Measurements, Recurring | Level 1 | U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	14,341	19,888
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	54,865	53,352
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities and commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	$ 54,865	$ 53,352

Accrued Liabilities - Summary o

Accrued Liabilities - Summary of Accrued Expenses and Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued research and development	$ 95	$ 197
Accrued professional fees	395	112
Accrued taxes and licenses	17	30
Accrued other	79	43
Total	$ 586	$ 382

Long-term Debt - Additional Inf

Long-term Debt - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Jun. 30, 2017
Debt Instrument [Line Items]
Amortization of debt discount	$ 44
Unamortized debt discount	$ 298
Series A-1 Preferred Stock Warrants
Debt Instrument [Line Items]
Warrants exercisable for shares of common stock (in shares)		7,069
Warrants issued, exercise price (in dollars per share)		$ 12.38
Fair value of warrant liability		$ 53
Series A-1 Preferred Stock Warrants | Common Stock
Debt Instrument [Line Items]
Warrants exercisable for shares of common stock (in shares)	7,069
Term Loan
Debt Instrument [Line Items]
Term loan debt		$ 5,000
Long-term debt final payment fee percentage	7.50%
Long-term debt final payment fee	$ 375
Term Loan | Prime Rate
Debt Instrument [Line Items]
Debt instrument variable interest rate	1.75%

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)	Jan. 31, 2018ft²option
Commitments and Contingencies Disclosure [Abstract]
Area of office and laboratory space under lease | ft²		6,184
Number of renewal options | option		2
Operating lease, annual base rent | $	$ 295
Percentage increase in lease each year	3.00%

License and Collaboration Agr42

License and Collaboration Agreement - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017	Oct. 20, 2017	Oct. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue	$ 315,000	$ 737,000
Accumulated deficit	(14,892,000)			$ (9,384,000)
Deferred revenue	240,000			$ 277,000
Kite | Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payments						$ 5,500,000
Collaboration revenue	240,000	$ 737,000
Kite | Collaboration Agreement | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone receivables (up to)	530,000,000
Kite | Amended Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible to receive additional research support payment					$ 450,000
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payments	(91,000)
Collaboration revenue	(112,000)
Accumulated deficit	$ 91,000		$ 203,000
Deferred revenue			$ 203,000

Stockholders' Deficit - Schedul

Stockholders' Deficit - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 511	$ 52
Employee | Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	197	13
Employee | General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	308	27
Non-Employee | Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1	12
Non-Employee | General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 5	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Jul. 24, 2017
Income Taxes [Line Items]
Effective tax rate	0.98%
U.S. federal statutory rate	21.00%
IPR&D acquired in business combination				$ 1,500,000
Income tax benefit	$ 52,000	$ 0
Federal research and development tax credits			$ 600,000
Federal
Income Taxes [Line Items]
Net operating loss carryforward			12,000,000
State
Income Taxes [Line Items]
Net operating loss carryforward			0
Nivalis Therapeutics, Inc.
Income Taxes [Line Items]
IPR&D acquired in business combination				1,453,000
Deferred tax liability, IPR&D			305,000	$ 509,000
IPR&D acquired in business combination, tax basis			$ 0
Net operating loss carryforward	$ 0