Annual report pursuant to Section 13 and 15(d)

Income Taxes - Schedule of Reconciliation of Income Taxes at Statutory Federal Income Tax Rate to Net Income Taxes (Detail)

v3.7.0.1
Income Taxes - Schedule of Reconciliation of Income Taxes at Statutory Federal Income Tax Rate to Net Income Taxes (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Income Tax Disclosure [Abstract]      
U.S. federal taxes (benefit) at statutory rate $ (8,192) $ 14,900 $ (7,407)
State federal income tax benefit (261) (448) (571)
Unutilized (utilized) net operating losses 7,238 (11,287) 9,809
Stock-based compensation 393 898 730
Research and development credits (1,552) (3,135) (952)
Tax assets not benefited 2,398 4,732 1,322
Nondeductible warrant expense (41) (5,703) (3,177)
Other 17 43 44
Total $ 0 $ 0 $ (202)