Fair Value - Summary of Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Assets measured at fair value
Cash and cash equivalents	$ 91,217	$ 24,165
Restricted cash	6,389	10,425
Total Assets measured at fair value	97,606	34,590
Liabilities measured at fair value
Contingent consideration	12,418	22,800
Warrant liabilities	14,090
Total liabilities measured at fair value	26,508	22,800
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets measured at fair value
Cash and cash equivalents	91,217	24,165
Restricted cash	6,389	10,425
Total Assets measured at fair value	97,606	34,590
Significant Unobservable Inputs (Level 3) [Member]
Liabilities measured at fair value
Contingent consideration	12,418	22,800
Warrant liabilities	14,090
Total liabilities measured at fair value	$ 26,508	$ 22,800