Net (Loss) Income Per Common Share - Schedule of Potential Dilutive Common Shares (Detail)	6 Months Ended
	Jun. 30, 2017 shares
Minimum [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	342,185,936
Minimum [Member] | Series A Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	10,065,629
Minimum [Member] | Series B Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	266,666,667
Maximum [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	419,392,284
Maximum [Member] | Series A Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	10,065,629
Maximum [Member] | Series B Preferred Stock Conversion Per Share Below 2.25 [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	1,015,872
Maximum [Member] | Series B Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	342,857,143
Restricted Shares Subject to Vesting [Member] | Minimum [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	4,053,640
Restricted Shares Subject to Vesting [Member] | Maximum [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	4,053,640
Warrants Outstanding [Member] | Minimum [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	61,400,000
Warrants Outstanding [Member] | Maximum [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive shares if converted to common stock	61,400,000