Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Significant Accounting Policies [Line Items]
Cash and cash equivalents in excess of insured limits	$ 109.4
Warrants
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share	2,116,250	2,116,250
Performance Awards
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share		9,469
Restricted Stock Units
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share	516,961
Performance Awards
Significant Accounting Policies [Line Items]
Shares, vesting period	3 years
Employee Stock Option
Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from the calculation of diluted earnings per share	6,915,865	5,675,393
Maximum
Significant Accounting Policies [Line Items]
Weighted average maturity period of short-term investments	1 year
Property and equipment, useful lives	5 years
Minimum
Significant Accounting Policies [Line Items]
Property and equipment, useful lives	3 years

Significant accounting policies.

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- Definition

Weighted average maturity period of short-term investments.

+ References

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Antidilution
-URI http://asc.fasb.org/extlink&oid=6505113

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Diluted Earnings Per Share
-URI http://asc.fasb.org/extlink&oid=6510752

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Contingent Stock Agreement
-URI http://asc.fasb.org/extlink&oid=6508534

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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- Definition

The amount of cash as of the balance sheet date that is not insured by the Federal Deposit Insurance Corporation.

+ References

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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