Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summary of Stock Option Activity (Detail)

v3.21.2
Stockholders' Equity - Summary of Stock Option Activity (Detail) - 2014 EIP and Inducement Plan - USD ($)
$ / shares in Units, $ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2021
Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Outstanding, Shares, beginning balance 7,851,886  
Granted, Shares 2,172,554  
Exercised, Shares (154,694)  
Forfeited or expired, Shares (411,592)  
Outstanding, Shares, ending balance 9,458,154 7,851,886
Outstanding, Weighted Average Exercise Price, beginning balance $ 22.89  
Granted, Weighted Average Exercise Price 16.14  
Exercised, Weighted Average Exercise Price 15.12  
Forfeited or expired, Weighted Average Exercise price 29.54  
Outstanding, Weighted Average Exercise Price, ending balance $ 21.18 $ 22.89
Outstanding, Weighted Average Remaining Contractual Term 6 years 8 months 12 days 6 years 4 months 24 days
Aggregate intrinsic value $ 12,367 $ 26,834