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Fair Value Measurements - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2017 USD ($) shares
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] |
Warrant liability | $ | $ 0
Maximum maturity period of cash and cash equivalents | 90 days
Maximum maturity period of short-term investments | 1 year
Series A and Series B Warrants issued in July 2014 Financing [Member] |
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] |
Warrants outstanding and exercisable | shares | 0
Maximum [Member] |
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] |
Maturity period of securities | 1 year

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- Definition Maximum maturity period of cash and cash equivalents. + References No definition available. + Details
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- Definition Number of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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- Definition Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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