Unaudited Condensed Statements of Operations and Comprehensive Loss (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Expenses:
Research and development	$ 5,170us-gaap_ResearchAndDevelopmentExpense	$ 1,996us-gaap_ResearchAndDevelopmentExpense
General and administrative	3,796us-gaap_GeneralAndAdministrativeExpense	3,134us-gaap_GeneralAndAdministrativeExpense
Total expenses	8,966us-gaap_CostsAndExpenses	5,130us-gaap_CostsAndExpenses
Loss from operations	(8,966)us-gaap_OperatingIncomeLoss	(5,130)us-gaap_OperatingIncomeLoss
Other income, net	11us-gaap_OtherNonoperatingIncomeExpense	2us-gaap_OtherNonoperatingIncomeExpense
Net loss and comprehensive loss	$ (8,955)	$ (5,128)
Basic and diluted net loss per share (usd per share)	$ (0.59)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.93)us-gaap_EarningsPerShareBasicAndDiluted
Shares used in computing basic and diluted net loss per share	15,242	5,535

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

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Total costs of sales and operating expenses for the period.

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-Name Accounting Standards Codification

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-SubTopic 10

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.4)

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The net result for the period of deducting operating expenses from operating revenues.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 9

-Article 5

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

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