Annual report pursuant to Section 13 and 15(d)

Financial Instruments - Reconciliation of Level 3 Measurement of Company's Primary Warrant (Detail)

v3.8.0.1
Financial Instruments - Reconciliation of Level 3 Measurement of Company's Primary Warrant (Detail) - Warrant [Member]
$ in Thousands
12 Months Ended
Dec. 31, 2017
USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]  
Beginning, Balance $ 7,114
Change in fair value of warrant liability $ (7,114)