Quarterly report pursuant to Section 13 or 15(d)

Stockholder's Equity - Summary of Common Stock Shares Activity (Detail)

v3.20.1
Stockholder's Equity - Summary of Common Stock Shares Activity (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Common Stock Outstanding Roll Forward [Roll Forward]    
Beginning balance $ 12,895 $ 31,225
Beginning balance (in shares) 97,413,721  
Net loss $ (7,002) (22,908)
Stock-based compensation expense 410 492
Common stock issued through employee stock purchase plan 18 20
Common stock issued, net of expenses $ 207 2,509
Common stock issued for exercise of stock options (in shares) 0  
Common stock issued for vested restricted stock units $ (73) (8)
Ending balance $ 6,455 11,330
Ending balance (in shares) 97,876,042  
Common Stock    
Common Stock Outstanding Roll Forward [Roll Forward]    
Beginning balance $ 97 $ 48
Beginning balance (in shares) 97,413,721 47,971,989
Net loss $ 0 $ 0
Stock-based compensation expense 0 0
Common stock issued through employee stock purchase plan $ 0 $ 0
Common stock issued through employee stock purchase plan (in shares) 22,143 19,259
Common stock issued, net of expenses $ 1 $ 2
Common stock issued, net of expenses (in shares) 285,276 2,226,569
Common stock issued for vested restricted stock units $ 0 $ 0
Common stock issued for vested restricted stock units (in shares) 154,902 14,612
Ending balance $ 98 $ 50
Ending balance (in shares) 97,876,042 50,232,429
Additional Paid-in Capital    
Common Stock Outstanding Roll Forward [Roll Forward]    
Beginning balance $ 284,226 $ 248,895
Net loss 0 0
Stock-based compensation expense 410 492
Common stock issued through employee stock purchase plan 18 20
Common stock issued, net of expenses 206 2,507
Common stock issued for vested restricted stock units (73) (8)
Ending balance 284,787 251,906
Accumulated Deficit    
Common Stock Outstanding Roll Forward [Roll Forward]    
Beginning balance (271,428) (217,718)
Net loss (7,002) (22,908)
Stock-based compensation expense 0 0
Common stock issued through employee stock purchase plan 0 0
Common stock issued, net of expenses 0 0
Common stock issued for vested restricted stock units 0 0
Ending balance $ (278,430) $ (240,626)