Document and Entity Information
Document and Entity Information - shares | 6 Months Ended | |
Jun. 30, 2015 | Jul. 31, 2015 | |
Document And Entity Information [Abstract] | ||
Document Type | 10-Q | |
Amendment Flag | false | |
Document Period End Date | Jun. 30, 2015 | |
Document Fiscal Year Focus | 2,015 | |
Document Fiscal Period Focus | Q2 | |
Trading Symbol | ATRA | |
Entity Registrant Name | Atara Biotherapeutics, Inc. | |
Entity Central Index Key | 1,604,464 | |
Current Fiscal Year End Date | --12-31 | |
Entity Filer Category | Non-accelerated Filer | |
Entity Common Stock, Shares Outstanding | 28,512,957 |
Condensed Consolidated Balance
Condensed Consolidated Balance Sheets - USD ($) $ in Thousands | Jun. 30, 2015 | Dec. 31, 2014 |
Current assets: | ||
Cash and cash equivalents | $ 26,190 | $ 21,897 |
Short-term available-for-sale investments | 128,841 | 82,219 |
Prepaid expenses and other current assets | 5,603 | 1,910 |
Total current assets | 160,634 | 106,026 |
Property and equipment, net | 42 | 48 |
Other assets | 426 | 48 |
Total assets | 161,102 | 106,122 |
Current liabilities: | ||
Accounts payable | 1,703 | 440 |
Accrued compensation | 924 | 1,225 |
Income tax payable | 1 | 1 |
License fee payable to Memorial Sloan Kettering Cancer Center ("MSK") | 4,500 | |
Other accrued liabilities | 4,516 | 1,058 |
Total current liabilities | 11,644 | 2,724 |
Other long-term liabilities | 203 | 216 |
Total liabilities | $ 11,847 | $ 2,940 |
Commitments and contingencies (Note 5) | ||
Stockholders’ equity: | ||
Preferred stock—$0.0001 par value, 20,000,000 shares authorized; none issued and outstanding as of June 30, 2015 and December 31, 2014 | ||
Common stock—$0.0001 par value, 500,000,000 shares authorized; 24,151,734 and 19,692,937 shares issued and outstanding as of June 30, 2015 and December 31, 2014, respectively | $ 2 | $ 2 |
Additional paid-in capital | 214,313 | 144,169 |
Accumulated other comprehensive loss | (66) | (100) |
Accumulated deficit | (64,994) | (40,889) |
Total stockholders’ equity | 149,255 | 103,182 |
Total liabilities and stockholders’ equity | $ 161,102 | $ 106,122 |
Condensed Consolidated Balance3
Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares | Jun. 30, 2015 | Dec. 31, 2014 |
Statement Of Financial Position [Abstract] | ||
Preferred stock, par value | $ 0.0001 | $ 0.0001 |
Preferred stock, shares authorized | 20,000,000 | 20,000,000 |
Preferred stock, shares issued | 0 | 0 |
Preferred stock, shares outstanding | 0 | 0 |
Common stock, par value | $ 0.0001 | $ 0.0001 |
Common Stock, shares authorized | 500,000,000 | 500,000,000 |
Common stock, shares issued | 24,151,734 | 19,692,937 |
Common stock, shares outstanding | 24,151,734 | 19,692,937 |
Condensed Consolidated and Comb
Condensed Consolidated and Combined Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | |
Expenses: | ||||
Research and development | $ 7,007 | $ 2,110 | $ 12,774 | $ 5,091 |
Research and development costs paid to Amgen | 1,066 | 1,066 | ||
In-process research and development license acquired from MSK | 4,500 | 4,500 | ||
General and administrative | 3,601 | 1,358 | 7,145 | 5,454 |
Total operating expenses | 15,108 | 4,534 | 24,419 | 11,611 |
Loss from operations | (15,108) | (4,534) | (24,419) | (11,611) |
Interest and other income | 163 | 23 | 316 | 29 |
Loss before provision for income taxes | (14,945) | (4,511) | (24,103) | (11,582) |
Provision (benefit) for income taxes | 2 | (22) | ||
Net loss | (14,945) | (4,511) | (24,105) | (11,560) |
Other comprehensive gain (loss), net of tax: | ||||
Unrealized gains (losses) on investments | (48) | 11 | 34 | |
Other comprehensive gain (loss) | (48) | 11 | 34 | |
Comprehensive loss | $ (14,993) | $ (4,500) | $ (24,071) | $ (11,560) |
Net loss per common share: | ||||
Basic and diluted net loss per common share | $ (0.62) | $ (3.37) | $ (1.04) | $ (8.89) |
Weighted-average common shares outstanding used to calculate basic and diluted net loss per common share | 24,224 | 1,337 | 23,079 | 1,300 |
Condensed Consolidated and Com5
Condensed Consolidated and Combined Statements of Cash Flows - USD ($) $ in Thousands | 6 Months Ended | |
Jun. 30, 2015 | Jun. 30, 2014 | |
Operating activities | ||
Net loss | $ (24,105) | $ (11,560) |
Adjustments to reconcile net loss to net cash used in operating activities: | ||
Depreciation expense | 11 | 2 |
Amortization of investment premiums and discounts | 880 | 138 |
Stock-based compensation expense | 5,053 | 3,844 |
Interest accrued on notes receivable from stockholder | (2) | |
Changes in operating assets and liabilities: | ||
Other assets | (24) | 1 |
Prepaid expenses and other current assets | (3,314) | (264) |
Accounts payable | 1,162 | (29) |
Income tax payable | (92) | |
Other accrued liabilities | 3,247 | 355 |
License fee payable to MSK | 4,500 | |
Accrued compensation | (301) | 28 |
Other long-term liabilities | 27 | |
Net cash used in operating activities | (12,864) | (7,579) |
Investing activities | ||
Purchase of short-term investments | (111,325) | (24,987) |
Maturities of short-term investments | 63,510 | |
Purchase of property and equipment | (5) | (5) |
Net cash used in investing activities | (47,820) | (24,992) |
Financing activities | ||
Proceeds from sale of common stock, net of offering costs | 69,487 | |
Taxes paid related to net share settlement of restricted stock units | (4,468) | |
Repayment of notes receivable from stockholder | 337 | |
Proceeds from sale of convertible preferred stock | 13,500 | |
Net cash provided by financing activities | 64,977 | 12,735 |
Increase (decrease) in cash and cash equivalents | 4,293 | (19,836) |
Cash and cash equivalents-beginning of period | 21,897 | 51,615 |
Cash and cash equivalents-end of period | 26,190 | 31,779 |
Non-cash financing activities | ||
Issuance of common stock upon vesting of stock awards | 40 | 45 |
Change in other long-term liabilities related to non-vested stock awards | (40) | (45) |
Proceeds receivable from option exercises | 32 | |
Offering costs in anticipation of public filing included in other accrued liabilities and accounts payable | 312 | 313 |
Supplemental cash flow disclosure—Cash paid for income taxes | 2 | 70 |
Follow-on Offering | ||
Financing activities | ||
Offering costs incurred | $ (42) | (1,083) |
Convertible Preferred Stock | ||
Financing activities | ||
Offering costs incurred | $ (19) |
Organization and Description of
Organization and Description of Business | 6 Months Ended |
Jun. 30, 2015 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Organization and Description of Business | 1. Organization and Description of Business Atara Biotherapeutics, Inc. (“Atara”, “we” or “our”) was incorporated in August 2012 in Delaware. We are a clinical-stage biopharmaceutical company focused on developing novel therapeutics for serious unmet medical needs, with an initial focus on muscle wasting conditions, oncology and viral-associated diseases. We have two groups of product candidates: molecularly targeted biologics and allogeneic, or third-party derived, antigen-specific T-cells, a type of white blood cell. In February 2015, we completed a follow-on offering of 4,147,358 shares of common stock at an offering price to the public of $18.00 per share. We received net proceeds of approximately $69.5 million, after deducting underwriting discounts and commissions and offering expenses. In July 2015, we completed a follow-on offering of 3,980,768 shares of common stock at an offering price to the public of $52.00 per share. We received net proceeds of approximately $193.9 million, after deducting underwriting discounts and commissions and offering expenses. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 6 Months Ended |
Jun. 30, 2015 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Basis of Presentation and Recapitalization The accompanying interim condensed consolidated and combined financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (the “SEC”). The accounting policies followed in the preparation of the interim condensed consolidated and combined financial statements are consistent in all material respects with those presented in Note 2 to the consolidated and combined financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. Atara was originally formed as a management company with the sole purpose of providing management, financial and administrative services for Nina Biotherapeutics, Inc. (“Nina”), Santa Maria Biotherapeutics, Inc. (“Santa Maria”) and Pinta Biotherapeutics, Inc. (“Pinta”). Prior to March 31, 2014, the accompanying financial statements include the operations of Atara, Nina, Pinta and Santa Maria on a combined basis as the four individual companies were under common ownership and common management since inception. All intercompany transactions have been eliminated. On March 31, 2014, our board of directors approved and we implemented a recapitalization (the “Recapitalization”) in which (a) all the outstanding shares of common stock of Atara were cancelled and forfeited by existing stockholders and (b) the stockholders of Nina, Pinta and Santa Maria exchanged their existing common and convertible preferred stock for newly-issued shares of Atara, with the same rights and privileges as the outstanding capital stock of Nina, Pinta and Santa Maria. The shares were exchanged on a collective nine-for-one basis. The Recapitalization lacked economic substance as the newly-issued shares have the same rights and privileges as the previously outstanding capital stock of Nina, Pinta and Santa Maria and there was no change in ownership percentages of the individual stockholders. As a result of the Recapitalization, Nina, Pinta and Santa Maria became wholly owned subsidiaries of Atara effective March 31, 2014. The Recapitalization is considered a tax-free exchange for US federal income tax purposes. Because the four individual companies were under common ownership and the Recapitalization lacked economic substance, we accounted for the Recapitalization as a combination of businesses under common control. The assets and liabilities of Nina, Pinta and Santa Maria were recorded by Atara at their historical carrying amounts on March 31, 2014 and beginning March 31, 2014, the financial statements of the Company are presented on a consolidated basis. Liquidity We have incurred significant operating losses since inception and have relied on public and private equity financings to fund our operations. At June 30, 2015, we had an accumulated deficit of $65.0 million. As we continue to incur losses, our transition to profitability will depend on the successful development, approval and commercialization of product candidates and on the achievement of sufficient revenues to support our cost structure. We may never achieve profitability, and unless and until we do, we will need to continue to raise additional capital. Management expects that existing cash and cash equivalents as of June 30, 2015 will be sufficient to fund our current operating plan for at least the next twelve months. Net Loss per Common Share Basic and diluted net loss per common share is presented, giving effect to the Recapitalization, including cancellation of existing Atara common stock and a nine-for-one share exchange. Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration of common stock equivalents. Diluted net loss per common share is computed by dividing the net loss by the weighted-average number of shares of common stock and common share equivalents outstanding for the period. Common share equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive. Our restricted stock awards are considered to be participating securities as they are entitled to participate in undistributed earnings with shares of common stock. Due to net losses, there is no impact on the net loss per common share calculation in applying the two-class method since the participating securities have no legal requirement to share in any losses. Potentially dilutive securities, which include convertible preferred stock, unvested restricted common stock awards, unvested restricted stock units and vested and unvested options have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per common share and be antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented. The following shares of potentially dilutive securities give effect to the Recapitalization, and have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive: Three months Six months ended June 30, ended June 30, 2015 2014 2015 2014 Convertible preferred stock — 12,298,535 — 12,223,577 Unvested restricted common stock 416,207 702,752 451,913 738,276 Unvested restricted stock units 564,821 — 599,162 — Vested and unvested options 470,094 — 287,346 — 1,451,122 13,001,287 1,338,421 12,961,853 In addition, 123,433 and 676,158 options have been excluded from the above table for the three and six months ended June 30, 2015, respectively, as the exercise prices of the underlying options were greater than the average fair value of our common stock for the periods presented. Recent Accounting Pronouncements In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-03, Interest- Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs The adoption of this standard is not expected to have a material impact on our financial statements In April 2015, the FASB issued ASU No. 2015-05, “ Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement” The adoption of this standard is not expected to have a material impact on our financial statements In August 2014, the FASB issued a new accounting standard to provide guidance on the presentation of management’s plans, when conditions or events raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. The new standard is effective for fiscal years ending after December 15, 2016. The adoption of this standard is not expected to have a material impact on our financial statements. In May 2014, the FASB issued a new accounting standard, Revenue from Contracts with Customers (Topic 606), Revenue Recognition |
Fair Value of Financial Instrum
Fair Value of Financial Instruments | 6 Months Ended |
Jun. 30, 2015 | |
Fair Value Disclosures [Abstract] | |
Fair Value of Financial Instruments | 3. Our financial assets and liabilities carried at fair value are primarily comprised of investments in money market funds, corporate bonds, U.S. government securities, asset-backed securities and commercial paper. The fair value accounting guidance requires that assets and liabilities be carried at fair value and classified in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities that we have the ability to access Level 2: Observable market based inputs or unobservable inputs that are corroborated by market data such as quoted prices, interest rates and yield curves Level 3: Inputs that are unobservable data points that are not corroborated by market data We review the fair value hierarchy classification on a quarterly basis. Changes in the ability to observe valuation inputs may result in a reclassification of levels of certain securities within the fair value hierarchy. We recognize transfers into and out of levels within the fair value hierarchy in the period in which the actual event or change in circumstances that caused the transfer occurs. There were no transfers between Level 1, Level 2, and Level 3 for all periods presented. The following table represents the fair value hierarchy for our financial assets and financial liabilities measured at fair value on a recurring basis: Quoted Significant Prices in Other Total Active Markets Observable Inputs Fair Value (Level 1) (Level 2) (in thousands) At June 30, 2015: Cash equivalents: Money market funds $ 25,880 $ 25,880 $ — Agency bonds 185 — 185 Corporate bonds 96 — 96 Total cash equivalents $ 26,161 $ 25,880 $ 281 Short-term available-for-sale investments: Corporate bonds $ 98,245 $ — $ 98,245 Agency bonds 17,513 — 17,513 Asset-backed securities 13,083 — 13,083 Total short-term available-for-sale investments $ 128,841 $ — $ 128,841 At December 31, 2014: Cash equivalents: Money market funds $ 18,141 $ 18,141 $ — Agency bonds 1,750 — 1,750 Corporate bonds 2,006 — 2,006 Total cash equivalents $ 21,897 $ 18,141 $ 3,756 Short-term available-for-sale investments: Corporate bonds $ 57,958 $ — $ 57,958 Agency bonds 10,764 — 10,764 Treasury bonds 465 — 465 Commercial paper 1,200 — 1,200 Asset-backed securities 11,832 — 11,832 Total short-term available-for-sale investments $ 82,219 $ — $ 82,219 Financial assets and liabilities are considered Level 2 when their fair values are determined using inputs that are observable in the market or can be derived principally from or corroborated by observable market data such as pricing for similar securities, recently executed transactions, cash flow models with yield curves, and benchmark securities. In addition, Level 2 financial instruments are valued using comparisons to like-kind financial instruments and models that use readily observable market data as their basis. Corporate bonds, U.S. government securities, asset-backed securities and commercial paper are valued primarily using market prices of comparable securities, bid/ask quotes, interest rate yields and prepayment spreads and are included in Level 2. Financial assets and liabilities are considered Level 3 when their fair values are determined using pricing models, discounted cash flow methodologies, or similar techniques, and at least one significant model assumption or input is unobservable. We have no Level 3 financial assets and liabilities. Short-term available-for-sale investments are carried at fair value and are included in the tables above under short-term investments. The aggregate market value, cost basis, and gross unrealized gains and losses of short-term available-for-sale investments by major security type are as follows: Total Total Total Amortized Unrealized Unrealized Total Cost Gain Loss Fair Value (in thousands) At June 30, 2015: Corporate bonds $ 98,321 $ 6 $ (82 ) $ 98,245 Agency bonds 17,507 9 (3 ) 17,513 Asset-backed securities 13,079 6 (2 ) 13,083 Total short-term available-for-sale investments $ 128,907 $ 21 $ (87 ) $ 128,841 At December 31, 2014: Corporate bonds $ 58,046 $ 1 $ (89 ) $ 57,958 Agency bonds 10,769 — (5 ) 10,764 Treasury bonds 466 — (1 ) 465 Commercial paper 1,200 — — 1,200 Asset-backed securities 11,838 2 (8 ) 11,832 Total short-term available-for-sale investments $ 82,319 $ 3 $ (103 ) $ 82,219 The amortized cost and fair value of short-term available-for-sale investments, by contractual maturity, were as follows: Total Amortized Total Cost Fair Value (in thousands) At June 30, 2015: Maturing within one year $ 86,980 $ 86,926 Maturing in one to five years 41,927 41,915 Total short-term available-for-sale investments $ 128,907 $ 128,841 At December 31, 2014: Maturing within one year $ 56,752 $ 56,714 Maturing in one to five years 25,567 25,505 Total short-term available-for-sale investments $ 82,319 $ 82,219 |
Significant Agreements
Significant Agreements | 6 Months Ended |
Jun. 30, 2015 | |
Related Party Transactions [Abstract] | |
Significant Agreements | 4. Significant Agreements Amgen License - In September 2012, we entered into three license agreements with Amgen, one of our investors, for the development, manufacturing, use and distribution of products using certain proprietary compounds. Under the terms of these agreements, we paid $250,000 and issued 5,538,462 shares of Series A-1 convertible preferred stock (615,384 shares after giving effect to the Recapitalization) to Amgen. We are obligated to make additional payments to Amgen of up to $86.0 million upon the achievement of certain development and regulatory approval milestones. Of these milestone payments, $14.0 million relate to milestones for clinical trials. The remaining $72.0 million relate to milestones for regulatory approvals in various territories and are anticipated to be made no earlier than 2017. Thereafter, we are obligated to make tiered payments based on achievement of commercial milestones based upon net sales levels. The maximum payments would be $206.0 million based on sales of over $1.0 billion for each of three products in a calendar year. We are also obligated to pay mid-single-digit percentage tiered royalties on future net sales of products which are developed and approved as defined by the agreements. Our royalty obligations as to a particular licensed product will be payable, on a country-by-country and product-by-product basis, until the later of (a) the date of expiration of the last to expire valid claim within the licensed patents that covers the manufacture, use or sale, offer to sell, or import of such licensed product by us or a sublicense in such country, (b) loss of regulatory exclusivity or (c) 10 years after the first commercial sale of the applicable licensed product in the applicable country. These agreements expire at the end of all royalty obligations to Amgen and, upon expiration, the licenses will be fully paid, royalty-free, irrevocable and non-exclusive. As of June 30, 2015 and December 31, 2014, there were no outstanding obligations due to Amgen. At June 30, 2015, Amgen owns approximately 6.0% of our outstanding voting capital stock. Amgen does not have any rights to participate in our product candidates’ development and is not represented on our board of directors. MSK Agreements – In September 2014, we entered into an exclusive option agreement with MSK under which we had the right to acquire the exclusive worldwide license rights to the three clinical stage T-cell therapies of MSK. The initial option period was for twelve months, with extensions available to extend the term up to 27 months at the option of Atara. Under the terms of the option agreement, we were obligated to use reasonable efforts to prepare a request to be submitted to the US Food and Drug Administration (the “FDA”) regarding a meeting to discuss pivotal trials for one of the clinical stage T-cell therapies. In exchange for the exclusive option, we paid MSK $1.25 million in cash and issued 59,761 shares of our common stock to MSK. At the time of issuance, we estimated the fair value of the common stock issued to MSK to be $750,000. This total of $2.0 million was recorded as research and development expense in our condensed consolidated and combined statement of operations and comprehensive loss in the third quarter of 2014. In June 2015, we exercised our option and entered into an exclusive license agreement with MSK. In connection with the execution of the License Agreement, Atara is obligated to make an upfront cash payment to MSK of $4.5 million and this amount has been recorded as research and development expense in our condensed consolidated and combined statement of operations and comprehensive loss in the second quarter of 2015. Atara is obligated to make additional payments of up to $33.0 million to MSK based on achievement of specified development, regulatory and sales-related milestones, as well as escalating mid single-digit royalties based on future sales of products resulting from the development of the licensed product candidates. In addition, under certain circumstances, we must make certain minimum annual royalty payments to MSK, which are creditable against earned royalties owed for the same annual period. We are also obligated to pay a low double-digit percentage of consideration we receive for sublicensing the licensed rights. The license agreement expires on a product-by-product and country-by-country basis on the later of: (i) expiration of the last licensed patent rights related to each licensed product, (ii) expiration of any market exclusivity period granted by law with respect to each licensed product, and (iii) a specified number of years after the first commercial sale of the licensed product in each country. Upon expiration of the license agreement, Atara will retain non-exclusive rights to the licensed products. Patent Obligations – Under the terms of our license agreements with Amgen and MSK, we pay costs related to the preparation, filing, prosecution, defense and maintenance of the patents covered by the license agreements. During the three months ended June 30, 2015 and 2014, we incurred expenses of $330,516 and $176,638, respectively, related to the preparation, filing and maintenance of patents. During the six months ended June 30, 2015 and 2014, patent costs were $839,434 and $394,710. These patent costs were recorded in the condensed consolidated and combined statement of operations and comprehensive loss as general and administrative expenses. |
Commitments and Contingencies
Commitments and Contingencies | 6 Months Ended |
Jun. 30, 2015 | |
Commitments And Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 5. Commitments and Contingencies Operating Leases Rent expense for the three months ended June 30, 2015 and 2014 was $98,226 and $15,113, respectively. Rent expense for the six months ended June 30, 2015 and 2014 was $179,446 and $29,753, respectively. Indemnification Agreements In the normal course of business, we enter into contracts and agreements that contain a variety of representations and warranties and provide for indemnification for certain liabilities. The exposure under these agreements is unknown because it involves claims that may be made against us in the future but have not yet been made. To date, we have not paid any claims or been required to defend any action related to our indemnification obligations. However, we may record charges in the future as a result of these indemnification obligations. We also have indemnification obligations to our directors and executive officers for specified events or occurrences, subject to some limits, while they are serving at our request in such capacities. There have been no claims to date and we believe the fair value of these indemnification agreements is minimal. Accordingly, we have not recorded any liabilities for these agreements as of June 30, 2015 and December 31, 2014. |
Stockholders' Equity
Stockholders' Equity | 6 Months Ended |
Jun. 30, 2015 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Stockholders’ Equity | 6. Stockholders’ Equity Restricted Common Stock In August 2012, in connection with our formation, our CEO purchased 9,595,384 shares of restricted common stock at a nominal per share purchase price. The shares were issued subject to certain vesting conditions, restrictions on transfer and a Company right of repurchase of any unvested share at their original purchase price. These shares are placed in escrow until vested, and have rights to vote and participate in dividends and distributions. The combined grant date intrinsic value for this award was $1,704,094 and 7,996,153 of these shares had service and fundraising vesting conditions. Under the service vesting condition, shares vest monthly over 48 months, commencing from the first closing of Series A convertible preferred stock financing on October 22, 2012. 1,599,231 of these shares are subject to performance milestones and fundraising vesting conditions. The fundraising vesting conditions for all shares were satisfied as of December 31, 2013. All shares subject to service vesting conditions are subject to accelerated vesting in the event of certain change of control transactions. In March 2013, an Atara employee purchased 2,423,074 shares of restricted common stock for $331,170. The shares were issued under our 2012 Equity Incentive Plan (as discussed below) and are subject to certain vesting conditions, restrictions on transfer and a Company right of repurchase of any unvested shares at their original purchase price. These shares are placed in escrow until vested, and have rights to vote and participate in dividends and distributions. Under these agreements, the shares vest as follows: 2,319,228 shares vest over four years, with one-quarter vesting after one year of service and the remainder vesting in equal installments over the subsequent thirty-six months, and 103,846 shares vest upon achievement of certain performance milestones. Vesting of all shares is subject to acceleration of vesting in the event of certain change of control transactions. The amounts paid for both restricted stock purchases were initially recorded as other long-term liabilities. As shares vest, we reclassify liabilities to equity and report shares as outstanding in the condensed consolidated and combined financial statements. On March 31, 2014, the shares were exchanged for 1,335,384 shares of Atara common stock. At June 30, 2015, 958,702 shares had vested and are classified as equity. Restricted stock shares not vested at June 30, 2015 totaled 376,683 shares and are expected to vest over two years. As both the Chief Executive Officer and the Atara employee were consultants of Nina, Pinta and Santa Maria through the Recapitalization date, we accounted for these awards as non-employee stock-based awards. Following the Recapitalization, these awards were accounted as employee awards based upon the fair market value of common stock on March 31, 2014. Stock-based compensation expense related to these awards is recorded using an accelerated graded vesting model and was $265,893 and $523,920 for the three months ended June 30, 2015 and 2014, respectively, and $589,119 and $3.8 million for the six months ended June 30, 2015 and 2014, respectively. The unrecognized stock-based compensation expense related to this unvested restricted stock was $594,642 at June 30, 2015 and this expense is expected to be recognized over a weighted-average period of 0.68 years. The aggregate intrinsic value of unvested restricted stock is $19.8 million at June 30, 2015. 2014 Equity Incentive Plans In March 2014, we adopted the 2014 Equity Incentive Plan (the “2014 plan”) as part of our Recapitalization. In connection with the Recapitalization, Atara assumed the plans of Nina, Pinta and Santa Maria and all outstanding restricted stock units (“RSUs”) and restricted stock awards granted under such plans. At the date of Recapitalization, RSUs and restricted stock awards issued by Nina, Pinta and Santa Maria to Atara employees became employee awards and the awards’ grant dates were established as the Recapitalization date. In May 2014, our board of directors amended and restated our 2014 plan and the amended plan became effective on October 15, 2014 upon the pricing of our initial public offering. The maximum number of shares of our common stock that may be issued pursuant to stock awards under the 2014 plan is 4,536,797 shares, including 1,294,041 shares that were previously available for issuance under the 2012 plans. The number of shares of our common stock reserved for issuance pursuant to stock awards under our 2014 plan will automatically increase on January 1 of each year for a period of up to ten years, beginning on January 1, 2015 and ending on and including January 1, 2024, by 5% of the number of shares of our capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by our board of directors. The number of shares of our common stock available for issuance under the 2014 plan is 2,061,228 at June 30, 2015. Under the terms of the 2014 plan, we may grant options, restricted stock awards and RSUs to employees, directors, consultants and other service providers. RSUs typically expire at the earlier of seven years from the date of grant or the service termination (or, for RSUs granted prior to February 2014, two years following the service termination date). Stock options are granted at prices no less than 100% of the estimated fair value of the shares on the date of grant as determined by the board of directors, provided, however, that the exercise price of an option granted to a 10% shareholder cannot be less than 110% of the estimated fair value of the shares on the date of grant. Options granted to employees and non-employees generally vest over four years and expire in seven years. Restricted Stock Units and Awards The RSUs granted prior to our initial public offering had a time-based service condition and a liquidity-based performance condition, and vest when both conditions are met. We determined that the liquidity-based performance condition was not probable of occurring and recorded no stock-based compensation expense related to the RSUs prior to our initial public offering. Upon the closing of our initial public offering in October 2014, we recorded $3.8 million of stock-based compensation expense in our consolidated and combined statement of operations and comprehensive loss for the quarter ended December 31, 2014. The remaining unrecognized stock-based compensation expense relating to nonvested RSUs will be recognized as the RSUs vest over the remaining service periods through 2018. As of June 30, 2015, there was $3.1 million of unrecognized stock-based compensation expense related to RSUs that is expected to be recognized over a weighted average period of 1.31 years. The aggregate intrinsic value of the RSUs outstanding at June 30, 2015 was $32.6 million. The following is a summary of RSU activity, including the restricted stock award discussed above, under our 2014 plan: Restricted Stock Awards RSUs Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2014 112,740 $ 0.40 619,303 $ 4.64 Granted — — 87,600 $ 25.15 Forfeited — — (2,645 ) 8.59 Vested (32,211 ) $ 0.40 (168,546 ) $ 5.92 Unvested at June 30, 2015 80,529 $ 0.40 535,712 $ 7.57 Under our RSU net settlement procedures, we withhold shares at settlement to cover the minimum payroll withholding obligations for employee income and other employment taxes. During 2015, we settled 285,259 RSUs, of which 281,391 RSUs were net settled by withholding 119,684 shares. The value of these withheld RSUs was $4.4 million, based on the closing price of our common stock on the settlement date. This amount was remitted to the appropriate taxing authorities and $4.4 million has been reflected as a financing activity in our consolidated and combined statement of cash flows. These withheld shares are no longer considered issued and outstanding, thereby reducing our shares outstanding used to calculated earnings per share, and these shares were returned to the shares reserved for issuance under our 2014 plan and are available for future issuance. Stock Options The following is a summary of option activity under our 2014 plan: Number of shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at December 31, 2014 623,936 $ 13.69 Granted (weighted-average grant date fair value of $15.32 per share) 802,099 27.09 Exercised (2,595 ) 12.55 Forfeited (3,758 ) 20.44 Balance at June 30, 2015 1,419,682 $ 21.25 6.45 $ 44,740,904 Stock options vested and expected to vest at June 30, 2015 1,419,682 $ 21.25 6.45 $ 44,740,904 Exercisable at June 30, 2015 118,380 $ 17.18 6.35 $ 4,211,691 Aggregate intrinsic value represents the difference between the closing stock price of our common stock on June 30, 2015 and the exercise price of outstanding, in-the-money options. The fair value of options issued during 2015 was estimated at the date of grant using the Black-Scholes valuation model with the following weighted-average assumptions: Three Months Ended June 30, 2015 Six Months Ended June 30, 2015 Employees Non Employees Employees Non Employees Risk-free interest rate 1.7% - 1.9% — 1.3% - 1.9% 1.6% Expected life of options in years 4.5 — 4.5 6.9 Expected volatility of underlying stock 71.9% - 73.4% — 71.1% - 73.4% 70.1% Expected dividend yield 0.0% — 0.0% 0.0% Stock-based Compensation Expense Total stock-based compensation expense related to all employee and non-employee awards was as follows (in thousands): Three months Six months ended June 30, ended June 30, 2015 2014 2015 2014 Research and development $ 1,251 $ 127 $ 2,540 $ 832 General and administrative 1,318 397 2,513 3,012 $ 2,569 $ 524 $ 5,053 $ 3,844 |
Summary of Significant Accoun12
Summary of Significant Accounting Policies (Policies) | 6 Months Ended |
Jun. 30, 2015 | |
Accounting Policies [Abstract] | |
Basis of Presentation and Recapitalization | Basis of Presentation and Recapitalization The accompanying interim condensed consolidated and combined financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (the “SEC”). The accounting policies followed in the preparation of the interim condensed consolidated and combined financial statements are consistent in all material respects with those presented in Note 2 to the consolidated and combined financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. Atara was originally formed as a management company with the sole purpose of providing management, financial and administrative services for Nina Biotherapeutics, Inc. (“Nina”), Santa Maria Biotherapeutics, Inc. (“Santa Maria”) and Pinta Biotherapeutics, Inc. (“Pinta”). Prior to March 31, 2014, the accompanying financial statements include the operations of Atara, Nina, Pinta and Santa Maria on a combined basis as the four individual companies were under common ownership and common management since inception. All intercompany transactions have been eliminated. On March 31, 2014, our board of directors approved and we implemented a recapitalization (the “Recapitalization”) in which (a) all the outstanding shares of common stock of Atara were cancelled and forfeited by existing stockholders and (b) the stockholders of Nina, Pinta and Santa Maria exchanged their existing common and convertible preferred stock for newly-issued shares of Atara, with the same rights and privileges as the outstanding capital stock of Nina, Pinta and Santa Maria. The shares were exchanged on a collective nine-for-one basis. The Recapitalization lacked economic substance as the newly-issued shares have the same rights and privileges as the previously outstanding capital stock of Nina, Pinta and Santa Maria and there was no change in ownership percentages of the individual stockholders. As a result of the Recapitalization, Nina, Pinta and Santa Maria became wholly owned subsidiaries of Atara effective March 31, 2014. The Recapitalization is considered a tax-free exchange for US federal income tax purposes. Because the four individual companies were under common ownership and the Recapitalization lacked economic substance, we accounted for the Recapitalization as a combination of businesses under common control. The assets and liabilities of Nina, Pinta and Santa Maria were recorded by Atara at their historical carrying amounts on March 31, 2014 and beginning March 31, 2014, the financial statements of the Company are presented on a consolidated basis. |
Substantial Doubt about Going Concern [Text Block] | Liquidity We have incurred significant operating losses since inception and have relied on public and private equity financings to fund our operations. At June 30, 2015, we had an accumulated deficit of $65.0 million. As we continue to incur losses, our transition to profitability will depend on the successful development, approval and commercialization of product candidates and on the achievement of sufficient revenues to support our cost structure. We may never achieve profitability, and unless and until we do, we will need to continue to raise additional capital. Management expects that existing cash and cash equivalents as of June 30, 2015 will be sufficient to fund our current operating plan for at least the next twelve months. |
Net Loss per Common Share | Net Loss per Common Share Basic and diluted net loss per common share is presented, giving effect to the Recapitalization, including cancellation of existing Atara common stock and a nine-for-one share exchange. Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration of common stock equivalents. Diluted net loss per common share is computed by dividing the net loss by the weighted-average number of shares of common stock and common share equivalents outstanding for the period. Common share equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive. Our restricted stock awards are considered to be participating securities as they are entitled to participate in undistributed earnings with shares of common stock. Due to net losses, there is no impact on the net loss per common share calculation in applying the two-class method since the participating securities have no legal requirement to share in any losses. Potentially dilutive securities, which include convertible preferred stock, unvested restricted common stock awards, unvested restricted stock units and vested and unvested options have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per common share and be antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented. The following shares of potentially dilutive securities give effect to the Recapitalization, and have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive: Three months Six months ended June 30, ended June 30, 2015 2014 2015 2014 Convertible preferred stock — 12,298,535 — 12,223,577 Unvested restricted common stock 416,207 702,752 451,913 738,276 Unvested restricted stock units 564,821 — 599,162 — Vested and unvested options 470,094 — 287,346 — 1,451,122 13,001,287 1,338,421 12,961,853 In addition, 123,433 and 676,158 options have been excluded from the above table for the three and six months ended June 30, 2015, respectively, as the exercise prices of the underlying options were greater than the average fair value of our common stock for the periods presented. |
Recent Accounting Pronouncements | Recent Accounting Pronouncements In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-03, Interest- Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs The adoption of this standard is not expected to have a material impact on our financial statements In April 2015, the FASB issued ASU No. 2015-05, “ Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement” The adoption of this standard is not expected to have a material impact on our financial statements In August 2014, the FASB issued a new accounting standard to provide guidance on the presentation of management’s plans, when conditions or events raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. The new standard is effective for fiscal years ending after December 15, 2016. The adoption of this standard is not expected to have a material impact on our financial statements. In May 2014, the FASB issued a new accounting standard, Revenue from Contracts with Customers (Topic 606), Revenue Recognition |
Summary of Significant Accoun13
Summary of Significant Accounting Policies (Tables) | 6 Months Ended |
Jun. 30, 2015 | |
Accounting Policies [Abstract] | |
Antidilutive Securities Excluded From Computation of Diluted Net Loss per Common Share | The following shares of potentially dilutive securities give effect to the Recapitalization, and have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive: Three months Six months ended June 30, ended June 30, 2015 2014 2015 2014 Convertible preferred stock — 12,298,535 — 12,223,577 Unvested restricted common stock 416,207 702,752 451,913 738,276 Unvested restricted stock units 564,821 — 599,162 — Vested and unvested options 470,094 — 287,346 — 1,451,122 13,001,287 1,338,421 12,961,853 |
Fair Value of Financial Instr14
Fair Value of Financial Instruments (Tables) | 6 Months Ended |
Jun. 30, 2015 | |
Fair Value Disclosures [Abstract] | |
Fair Value Hierarchy for Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis | The following table represents the fair value hierarchy for our financial assets and financial liabilities measured at fair value on a recurring basis: Quoted Significant Prices in Other Total Active Markets Observable Inputs Fair Value (Level 1) (Level 2) (in thousands) At June 30, 2015: Cash equivalents: Money market funds $ 25,880 $ 25,880 $ — Agency bonds 185 — 185 Corporate bonds 96 — 96 Total cash equivalents $ 26,161 $ 25,880 $ 281 Short-term available-for-sale investments: Corporate bonds $ 98,245 $ — $ 98,245 Agency bonds 17,513 — 17,513 Asset-backed securities 13,083 — 13,083 Total short-term available-for-sale investments $ 128,841 $ — $ 128,841 At December 31, 2014: Cash equivalents: Money market funds $ 18,141 $ 18,141 $ — Agency bonds 1,750 — 1,750 Corporate bonds 2,006 — 2,006 Total cash equivalents $ 21,897 $ 18,141 $ 3,756 Short-term available-for-sale investments: Corporate bonds $ 57,958 $ — $ 57,958 Agency bonds 10,764 — 10,764 Treasury bonds 465 — 465 Commercial paper 1,200 — 1,200 Asset-backed securities 11,832 — 11,832 Total short-term available-for-sale investments $ 82,219 $ — $ 82,219 |
Short Term Available for Sale Investments Carried at Fair Value Included Short Term Investments | Short-term available-for-sale investments are carried at fair value and are included in the tables above under short-term investments. The aggregate market value, cost basis, and gross unrealized gains and losses of short-term available-for-sale investments by major security type are as follows: Total Total Total Amortized Unrealized Unrealized Total Cost Gain Loss Fair Value (in thousands) At June 30, 2015: Corporate bonds $ 98,321 $ 6 $ (82 ) $ 98,245 Agency bonds 17,507 9 (3 ) 17,513 Asset-backed securities 13,079 6 (2 ) 13,083 Total short-term available-for-sale investments $ 128,907 $ 21 $ (87 ) $ 128,841 At December 31, 2014: Corporate bonds $ 58,046 $ 1 $ (89 ) $ 57,958 Agency bonds 10,769 — (5 ) 10,764 Treasury bonds 466 — (1 ) 465 Commercial paper 1,200 — — 1,200 Asset-backed securities 11,838 2 (8 ) 11,832 Total short-term available-for-sale investments $ 82,319 $ 3 $ (103 ) $ 82,219 |
Amortized Cost and Fair Value of Short Term Available for Sale Investments by Contractual Maturity | The amortized cost and fair value of short-term available-for-sale investments, by contractual maturity, were as follows: Total Amortized Total Cost Fair Value (in thousands) At June 30, 2015: Maturing within one year $ 86,980 $ 86,926 Maturing in one to five years 41,927 41,915 Total short-term available-for-sale investments $ 128,907 $ 128,841 At December 31, 2014: Maturing within one year $ 56,752 $ 56,714 Maturing in one to five years 25,567 25,505 Total short-term available-for-sale investments $ 82,319 $ 82,219 |
Stockholders' Equity (Tables)
Stockholders' Equity (Tables) | 6 Months Ended |
Jun. 30, 2015 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Summary of RSU Activity and Restricted Stock Award | The following is a summary of RSU activity, including the restricted stock award discussed above, under our 2014 plan: Restricted Stock Awards RSUs Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2014 112,740 $ 0.40 619,303 $ 4.64 Granted — — 87,600 $ 25.15 Forfeited — — (2,645 ) 8.59 Vested (32,211 ) $ 0.40 (168,546 ) $ 5.92 Unvested at June 30, 2015 80,529 $ 0.40 535,712 $ 7.57 |
Summary of Stock Option Activity | The following is a summary of option activity under our 2014 plan: Number of shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at December 31, 2014 623,936 $ 13.69 Granted (weighted-average grant date fair value of $15.32 per share) 802,099 27.09 Exercised (2,595 ) 12.55 Forfeited (3,758 ) 20.44 Balance at June 30, 2015 1,419,682 $ 21.25 6.45 $ 44,740,904 Stock options vested and expected to vest at June 30, 2015 1,419,682 $ 21.25 6.45 $ 44,740,904 Exercisable at June 30, 2015 118,380 $ 17.18 6.35 $ 4,211,691 |
Summary of Options Estimated with Weighted Average | The fair value of options issued during 2015 was estimated at the date of grant using the Black-Scholes valuation model with the following weighted-average assumptions: Three Months Ended June 30, 2015 Six Months Ended June 30, 2015 Employees Non Employees Employees Non Employees Risk-free interest rate 1.7% - 1.9% — 1.3% - 1.9% 1.6% Expected life of options in years 4.5 — 4.5 6.9 Expected volatility of underlying stock 71.9% - 73.4% — 71.1% - 73.4% 70.1% Expected dividend yield 0.0% — 0.0% 0.0% |
Schedule of Stock-based Compensation, Nonemployee Director Stock Award Plan, Activity | Total stock-based compensation expense related to all employee and non-employee awards was as follows (in thousands): Three months Six months ended June 30, ended June 30, 2015 2014 2015 2014 Research and development $ 1,251 $ 127 $ 2,540 $ 832 General and administrative 1,318 397 2,513 3,012 $ 2,569 $ 524 $ 5,053 $ 3,844 |
Organization and Description 16
Organization and Description of Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 1 Months Ended | 6 Months Ended | |
Jul. 31, 2015 | Feb. 28, 2015 | Jun. 30, 2015 | |
Organization And Description Of Business [Line Items] | |||
Entity incorporation state | Delaware | ||
Entity incorporation date | Aug. 1, 2012 | ||
Net proceeds from sale of common stock | $ 69,487 | ||
Follow-on Offering | |||
Organization And Description Of Business [Line Items] | |||
Common stock, shares issued | 4,147,358 | ||
Shares issued, price per share | $ 18 | ||
Net proceeds from sale of common stock | $ 69,500 | ||
Follow-on Offering | Subsequent Event | |||
Organization And Description Of Business [Line Items] | |||
Common stock, shares issued | 3,980,768 | ||
Shares issued, price per share | $ 52 | ||
Net proceeds from sale of common stock | $ 193,900 |
Summary of Significant Accoun17
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | |
Jun. 30, 2015 | Jun. 30, 2015 | Dec. 31, 2014 | |
Significant Accounting Policies [Line Items] | |||
Stock conversion ratio | Nine-for-one basis | ||
Accumulated deficit | $ 64,994 | $ 64,994 | $ 40,889 |
Employee Stock Option | |||
Significant Accounting Policies [Line Items] | |||
Antidilutive securities excluded from computation of earnings per share, amount | 123,433 | 676,158 |
Summary of Significant Accoun18
Summary of Significant Accounting Policies - Antidilutive Securities Excluded From Computation of Diluted Net Loss per Common Share (Detail) - shares | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive securities excluded from computation of earnings per share, amount | 1,451,122 | 13,001,287 | 1,338,421 | 12,961,853 |
Convertible Preferred Stock | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive securities excluded from computation of earnings per share, amount | 12,298,535 | 12,223,577 | ||
Unvested Restricted Common Stock | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive securities excluded from computation of earnings per share, amount | 416,207 | 702,752 | 451,913 | 738,276 |
Unvested Restricted Stock Units | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive securities excluded from computation of earnings per share, amount | 564,821 | 599,162 | ||
Vested and Unvested Options | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive securities excluded from computation of earnings per share, amount | 470,094 | 287,346 |
Fair Value of Financial Instr19
Fair Value of Financial Instruments - Fair Value Hierarchy for Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands | Jun. 30, 2015 | Dec. 31, 2014 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | $ 128,841 | $ 82,219 |
Agency Bonds | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 17,513 | 10,764 |
Corporate Bonds | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 98,245 | 57,958 |
Treasury Bonds | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 465 | |
Commercial Paper | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 1,200 | |
Asset-Backed Securities | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 13,083 | 11,832 |
Fair Value, Measurements, Recurring | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 26,161 | 21,897 |
Short-term available-for-sale investments | 128,841 | 82,219 |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 25,880 | 18,141 |
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 281 | 3,756 |
Short-term available-for-sale investments | 128,841 | 82,219 |
Fair Value, Measurements, Recurring | Money Market Funds | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 25,880 | 18,141 |
Fair Value, Measurements, Recurring | Money Market Funds | Quoted Prices in Active Markets (Level 1) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 25,880 | 18,141 |
Fair Value, Measurements, Recurring | Agency Bonds | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 185 | 1,750 |
Short-term available-for-sale investments | 17,513 | 10,764 |
Fair Value, Measurements, Recurring | Agency Bonds | Significant Other Observable Inputs (Level 2) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 185 | 1,750 |
Short-term available-for-sale investments | 17,513 | 10,764 |
Fair Value, Measurements, Recurring | Corporate Bonds | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 96 | 2,006 |
Short-term available-for-sale investments | 98,245 | 57,958 |
Fair Value, Measurements, Recurring | Corporate Bonds | Significant Other Observable Inputs (Level 2) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Cash equivalents | 96 | 2,006 |
Short-term available-for-sale investments | 98,245 | 57,958 |
Fair Value, Measurements, Recurring | Treasury Bonds | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 465 | |
Fair Value, Measurements, Recurring | Treasury Bonds | Significant Other Observable Inputs (Level 2) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 465 | |
Fair Value, Measurements, Recurring | Commercial Paper | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 1,200 | |
Fair Value, Measurements, Recurring | Commercial Paper | Significant Other Observable Inputs (Level 2) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 1,200 | |
Fair Value, Measurements, Recurring | Asset-Backed Securities | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | 13,083 | 11,832 |
Fair Value, Measurements, Recurring | Asset-Backed Securities | Significant Other Observable Inputs (Level 2) | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Short-term available-for-sale investments | $ 13,083 | $ 11,832 |
Fair Value of Financial Instr20
Fair Value of Financial Instruments - Short-Term Available-for-Sale Investments Carried at Fair Value Included Short Term Investments (Detail) - USD ($) $ in Thousands | Jun. 30, 2015 | Dec. 31, 2014 |
Schedule of Available-for-sale Securities [Line Items] | ||
Total Amortized Cost | $ 128,907 | $ 82,319 |
Total Unrealized Gain | 21 | 3 |
Total Unrealized Loss | (87) | (103) |
Total Fair Value | 128,841 | 82,219 |
Corporate Bonds | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Total Amortized Cost | 98,321 | 58,046 |
Total Unrealized Gain | 6 | 1 |
Total Unrealized Loss | (82) | (89) |
Total Fair Value | 98,245 | 57,958 |
Agency Bonds | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Total Amortized Cost | 17,507 | 10,769 |
Total Unrealized Gain | 9 | |
Total Unrealized Loss | (3) | (5) |
Total Fair Value | 17,513 | 10,764 |
Treasury Bonds | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Total Amortized Cost | 466 | |
Total Unrealized Loss | (1) | |
Total Fair Value | 465 | |
Commercial Paper | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Total Amortized Cost | 1,200 | |
Total Fair Value | 1,200 | |
Asset-Backed Securities | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Total Amortized Cost | 13,079 | 11,838 |
Total Unrealized Gain | 6 | 2 |
Total Unrealized Loss | (2) | (8) |
Total Fair Value | $ 13,083 | $ 11,832 |
Fair Value of Financial Instr21
Fair Value of Financial Instruments - Amortized Cost and Fair Value of Short-Term Available-for-Sale Investments by Contractual Maturity (Detail) - USD ($) $ in Thousands | Jun. 30, 2015 | Dec. 31, 2014 |
Amortized cost | ||
Maturing within one year, Amortized cost | $ 86,980 | $ 56,752 |
Maturing in one to five years, Amortized cost | 41,927 | 25,567 |
Total short-term available-for-sale investments, Amortized cost | 128,907 | 82,319 |
Fair value | ||
Maturing within one year, Fair value | 86,926 | 56,714 |
Maturing in one to five years, Fair value | 41,915 | 25,505 |
Total short-term available-for-sale investments, Fair value | $ 128,841 | $ 82,219 |
Significant Agreements - Additi
Significant Agreements - Additional Information (Detail) - USD ($) | Sep. 30, 2012 | Jun. 30, 2015 | Sep. 30, 2014 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Dec. 31, 2014 |
Related Party Transaction [Line Items] | |||||||
Research and development expense | $ 4,500,000 | $ 4,500,000 | |||||
Memorial Sloan Kettering Cancer Center | |||||||
Related Party Transaction [Line Items] | |||||||
Share issued under the agreements | 59,761 | ||||||
Payments under license agreement | $ 4,500,000 | ||||||
Exclusive option agreement, initial term | 12 months | ||||||
Exclusive option agreement, extension term | 27 months | ||||||
Payments under exclusive option license agreement | $ 1,250,000 | ||||||
Fair value of the common stock issued | 750,000 | ||||||
Research and development expense | $ 2,000,000 | ||||||
Estimated future payment for license fee | 33,000,000 | ||||||
License Agreements | |||||||
Related Party Transaction [Line Items] | |||||||
Payments under license agreement | 330,516 | $ 176,638 | 839,434 | $ 394,710 | |||
License Agreements | Amgen | |||||||
Related Party Transaction [Line Items] | |||||||
Payments under license agreement | $ 250,000 | ||||||
Milestone payment payable on achievement of development and regulatory approvals | 86,000,000 | 86,000,000 | |||||
Sales revenue | 1,000,000,000 | ||||||
Contractual obligations due | $ 0 | $ 0 | $ 0 | ||||
Percentage of common stock | 6.00% | 6.00% | |||||
License Agreements | Amgen | Series A-1 Convertible Preferred Stock | Prior to Recapitalization | |||||||
Related Party Transaction [Line Items] | |||||||
Share issued under the agreements | 5,538,462 | ||||||
License Agreements | Amgen | Series A-1 Convertible Preferred Stock | After Recapitalization | |||||||
Related Party Transaction [Line Items] | |||||||
Share issued under the agreements | 615,384 | ||||||
License Agreements | Amgen | Maximum | |||||||
Related Party Transaction [Line Items] | |||||||
Milestone payment payable on achievement of development and regulatory approvals | $ 206,000,000 | $ 206,000,000 | |||||
License Agreements | Amgen | Milestone For Clinical Trials | |||||||
Related Party Transaction [Line Items] | |||||||
Milestone payment payable on achievement of development and regulatory approvals | 14,000,000 | 14,000,000 | |||||
License Agreements | Amgen | Favorable Regulatory Action | |||||||
Related Party Transaction [Line Items] | |||||||
Milestone payment payable on achievement of development and regulatory approvals | $ 72,000,000 | $ 72,000,000 |
Commitments and Contingencies -
Commitments and Contingencies - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended | |||
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Dec. 31, 2014 | |
Commitments And Contingencies Disclosure [Abstract] | |||||
Rental expense | $ 98,226 | $ 15,113 | $ 179,446 | $ 29,753 | |
Liabilities related to indemnification agreements | $ 0 | $ 0 | $ 0 |
Stockholders' Equity - Addition
Stockholders' Equity - Additional Information (Detail) - USD ($) | 1 Months Ended | 3 Months Ended | 6 Months Ended | ||||||
Oct. 31, 2014 | Mar. 31, 2013 | Aug. 31, 2012 | Jun. 30, 2015 | Jun. 30, 2014 | Mar. 31, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Dec. 31, 2014 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Common stock, shares issued | 24,151,734 | 24,151,734 | 19,692,937 | ||||||
Proceeds from sale of common stock, net of offering costs | $ 69,487,000 | ||||||||
Stock-based compensation expense | $ 2,569,000 | $ 524,000 | 5,053,000 | $ 3,844,000 | |||||
Aggregate intrinsic value | $ 44,740,904 | $ 44,740,904 | |||||||
Estimated fair value of the shares on the date of grant | 100.00% | ||||||||
Stock option granted description terms | the exercise price of an option granted to a 10% shareholder cannot be less than 110% of the estimated fair value of the shares on the date of grant. Options granted to employees and non-employees generally vest over four years and expire in seven years. | ||||||||
Minimum | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Estimated fair value of the shares on the date of grant | 10.00% | ||||||||
Maximum | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Estimated fair value of the shares on the date of grant | 110.00% | ||||||||
2012 Equity Incentive Plan | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Common stock, reserved for issuance | 1,294,041 | 1,294,041 | |||||||
2014 Equity Incentive Plan | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Common stock, shares issued | 4,536,797 | 4,536,797 | |||||||
Common stock, reserved for issuance | 2,061,228 | 2,061,228 | |||||||
Share based compensation award expiration period | 10 years | ||||||||
Capital stock reserved for issuance, percentage of number of shares of capital stock outstanding | 5.00% | ||||||||
Unvested Restricted Common Stock | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Combined grant date intrinsic value for award | $ 1,704,094 | ||||||||
Share based compensation, vesting period | 2 years | ||||||||
Vested restricted stock awards | 32,211 | ||||||||
Unvested restricted stock awards | 80,529 | 80,529 | 112,740 | ||||||
Unrecognized stock-based compensation expense | $ 594,642 | $ 594,642 | |||||||
Unrecognized stock-based compensation weighted average recognition period | 8 months 5 days | ||||||||
Aggregate intrinsic value | $ 19,800,000 | $ 19,800,000 | |||||||
Unvested Restricted Common Stock | Prior to Recapitalization | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Shares exchanged | 1,335,384 | ||||||||
Vested restricted stock awards | 958,702 | ||||||||
Unvested restricted stock awards | 376,683 | 376,683 | |||||||
Unvested Restricted Common Stock | 2012 Equity Incentive Plan | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Proceeds from sale of common stock, net of offering costs | $ 331,170 | ||||||||
Share-based compensation, number of shares expected to vest | 2,319,228 | ||||||||
Employees And Non Employees | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Share based compensation, vesting period | 4 years | 4 years | |||||||
Share based compensation award expiration period | 7 years | ||||||||
Unvested Restricted Stock Units | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Vested restricted stock awards | 168,546 | ||||||||
Unvested restricted stock awards | 535,712 | 535,712 | 619,303 | ||||||
Stock-based compensation expense | $ 3,800,000 | ||||||||
Unrecognized stock-based compensation expense | $ 3,100,000 | $ 3,100,000 | |||||||
Unrecognized stock-based compensation weighted average recognition period | 1 year 3 months 22 days | ||||||||
Aggregate intrinsic value | 32,600,000 | $ 32,600,000 | |||||||
Restricted stock units, settled | 285,259 | ||||||||
Restricted stock units, issued net of tax withholdings | 281,391 | ||||||||
Restricted stock units withheld for tax obligations | 119,684 | ||||||||
Restricted stock units withheld for tax obligations, value | $ 4,400,000 | ||||||||
Stock Options | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Unrecognized stock-based compensation weighted average recognition period | 3 years 2 months 19 days | ||||||||
Unrecognized stock-based compensation | 14,900,000 | $ 14,900,000 | |||||||
Performance milestones and fundraising vesting conditions | Unvested Restricted Common Stock | 2012 Equity Incentive Plan | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Share-based compensation, number of shares expected to vest | 103,846 | ||||||||
Service and Performance Conditions | Unvested Restricted Common Stock | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Stock-based compensation expense | $ 265,893 | $ 523,920 | $ 589,119 | $ 3,800,000 | |||||
From Date Of Grant | Unvested Restricted Stock Units | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Share based compensation award expiration period | 7 years | ||||||||
Following Service Termination Date | Unvested Restricted Stock Units | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Share based compensation award expiration period | 2 years | ||||||||
Chief Executive Officer | Unvested Restricted Common Stock | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Common stock, shares issued | 9,595,384 | ||||||||
Share based compensation, vesting period | 48 months | ||||||||
Chief Executive Officer | Performance milestones and fundraising vesting conditions | Unvested Restricted Common Stock | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Common stock, shares issued | 1,599,231 | ||||||||
Chief Executive Officer | Service and fundraising vesting conditions | Unvested Restricted Common Stock | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Common stock, shares issued | 7,996,153 | ||||||||
Atara Employee | Unvested Restricted Common Stock | 2012 Equity Incentive Plan | |||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||||
Common stock, shares issued | 2,423,074 |
Stockholders' Equity - Summary
Stockholders' Equity - Summary of RSU Activity and Restricted Stock Award (Detail) - 6 months ended Jun. 30, 2015 - $ / shares | Total |
Restricted Stock Awards | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |
Unvested at December 31, 2014 | 112,740 |
Vested | (32,211) |
Unvested at June 30, 2015 | 80,529 |
Unvested at December 31, 2014 | $ 0.40 |
Vested | 0.40 |
Unvested at June 30, 2015 | $ 0.40 |
Unvested Restricted Stock Units | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |
Unvested at December 31, 2014 | 619,303 |
Granted | 87,600 |
Forfeited | (2,645) |
Vested | (168,546) |
Unvested at June 30, 2015 | 535,712 |
Unvested at December 31, 2014 | $ 4.64 |
Granted | 25.15 |
Forfeited | 8.59 |
Vested | 5.92 |
Unvested at June 30, 2015 | $ 7.57 |
Stockholders' Equity - Summar26
Stockholders' Equity - Summary of Stock Option Activity (Detail) - Jun. 30, 2015 - USD ($) | Total |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Outstanding, Number of shares, beginning balance | 623,936 |
Granted, Number of shares | 802,099 |
Exercised, Number of share | (2,595) |
Forfeited, Number of share | (3,758) |
Outstanding, Number of shares, ending balance | 1,419,682 |
Stock options vested and expected to vest, Number of shares | 1,419,682 |
Exercisable, Number of shares | 118,380 |
Outstanding, Weighted Average Exercise Price, beginning balance | $ 13.69 |
Granted, Weighted Average Exercise Price | 27.09 |
Exercised, Weighted Average Exercise Price | 12.55 |
Forfeited, Weighted Average Exercise price | 20.44 |
Outstanding, Weighted Average Exercise Price, ending balance | 21.25 |
Stock options vested and expected to vest, Weighted Average Exercise Price | 21.25 |
Exercisable, Weighted Average Exercise Price | $ 17.18 |
Outstanding, Weighted Average Remaining Contractual Term | 6 years 5 months 12 days |
Stock options vested and expected to vest, Weighted Average Remaining Contractual Term | 6 years 5 months 12 days |
Exercisable, Weighted Average Remaining Contractual Term | 6 years 4 months 6 days |
Outstanding, Aggregate Intrinsic Value | $ 44,740,904 |
Stock options vested and expected to vest, Aggregate Intrinsic Value | 44,740,904 |
Exercisable, Aggregate Intrinsic Value | $ 4,211,691 |
Stockholders' Equity - Summar27
Stockholders' Equity - Summary of Stock Option Activity (Parenthetical) (Detail) | 6 Months Ended |
Jun. 30, 2015$ / shares | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Weighted-average grant date fair value per share | $ 15.32 |
Stockholders' Equity - Summar28
Stockholders' Equity - Summary of Estimated Weighted-Average Assumptions (Detail) - Jun. 30, 2015 | Total | Total |
Employee | ||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Risk-free interest rate, minimum | 1.70% | 1.30% |
Risk-free interest rate, maximum | 1.90% | 1.90% |
Expected life of options in years | 4 years 6 months | 4 years 6 months |
Expected volatility of underlying stock, minimum | 71.90% | 71.10% |
Expected volatility of underlying stock, maximum | 73.40% | 73.40% |
Expected dividend yield | 0.00% | 0.00% |
Non Employees | ||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Risk-free interest rate | 1.60% | |
Expected life of options in years | 6 years 10 months 24 days | |
Expected volatility of underlying stock, minimum | 70.10% | |
Expected dividend yield | 0.00% |
Stockholders' Equity - Schedule
Stockholders' Equity - Schedule of Stock-based Compensation Related to All Employee and Non-Employee Awards (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
Stock-based compensation expense | $ 2,569 | $ 524 | $ 5,053 | $ 3,844 |
Research and Development | ||||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
Stock-based compensation expense | 1,251 | 127 | 2,540 | 832 |
General and Administrative | ||||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||||
Stock-based compensation expense | $ 1,318 | $ 397 | $ 2,513 | $ 3,012 |