Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.2
Stockholder's Equity - Summary of Common Stock Shares Activity (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 6,333 $ 10,402 $ 12,895 $ 31,225
Beginning balance (in shares)     9,741,372  
Net income (loss) 909 (7,941) $ (12,474) (39,252)
Stock-based compensation expense 399 449 1,220 1,387
Common stock issued through employee stock purchase and stock option plans     28  
Common stock issued, net of expenses 1,909 3,206 $ 4,578 9,761
Common stock issued through employee stock purchase plan 9 17   37
Common stock issued for exercise of stock options   12   12
Common stock issued for exercise of stock options (in shares)     166  
Common stock issued for Commitment Shares     $ 602  
Common stock issued for vested restricted stock units (1) (2) (75) (11)
Ending balance $ 9,558 6,143 $ 9,558 6,143
Ending balance (in shares) 10,798,119   10,798,119  
April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     $ 2,784  
March 2019 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes       2,984
Common Stock        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 10 $ 5 $ 10 $ 5
Beginning balance (in shares) 10,478,927 5,452,011 9,741,372 4,797,198
Net income (loss) $ 0 $ 0 $ 0 $ 0
Stock-based compensation expense 0 0 0 0
Common stock issued through employee stock purchase and stock option plans     $ 0  
Common stock issued through employee stock purchase and stock option plans (in shares)     4,652  
Common stock issued, net of expenses $ 0 $ 0 $ 0 $ 0
Common stock issued, net of expenses (in shares) 315,939 279,911 647,504 768,658
Common stock issued through employee stock purchase plan $ 0 $ 0   $ 0
Common stock issued through employee stock purchase plan (in shares) 2,284 1,758   3,684
Common stock issued for exercise of stock options   $ 0   $ 0
Common stock issued for exercise of stock options (in shares)   2,250   2,250
Common stock issued for Commitment Shares     $ 0  
Common stock issued for Commitment Shares (in shares)     70,910  
Common stock issued for vested restricted stock units $ 0 $ 0 $ 0 $ 0
Common stock issued for vested restricted stock units (in shares) 969 312 17,220 1,852
Ending balance $ 10 $ 5 $ 10 $ 5
Ending balance (in shares) 10,798,119 5,736,242 10,798,119 5,736,242
Common Stock | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     $ 0  
Common stock issued for conversion of Notes (in shares)     316,461  
Common Stock | March 2019 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes       $ 0
Common stock issued for conversion of Notes (in shares)       162,600
Additional Paid-in Capital        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 291,134 $ 259,426 $ 284,313 $ 248,938
Net income (loss) 0 0 0 0
Stock-based compensation expense 399 449 1,220 1,387
Common stock issued through employee stock purchase and stock option plans     28  
Common stock issued, net of expenses 1,909 3,206 4,578 9,761
Common stock issued through employee stock purchase plan 9 17   37
Common stock issued for exercise of stock options   12   12
Common stock issued for Commitment Shares     602  
Common stock issued for vested restricted stock units (1) (2) (75) (11)
Ending balance 293,450 263,108 293,450 263,108
Additional Paid-in Capital | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     2,784  
Additional Paid-in Capital | March 2019 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes       2,984
Accumulated Deficit        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance (284,811) (249,029) (271,428) (217,718)
Net income (loss) 909 (7,941) (12,474) (39,252)
Stock-based compensation expense 0 0 0 0
Common stock issued through employee stock purchase and stock option plans     0  
Common stock issued, net of expenses 0 0 0 0
Common stock issued through employee stock purchase plan 0 0   0
Common stock issued for exercise of stock options   0   0
Common stock issued for Commitment Shares     0  
Common stock issued for vested restricted stock units 0 0 0 0
Ending balance $ (283,902) $ (256,970) (283,902) (256,970)
Accumulated Deficit | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     $ 0  
Accumulated Deficit | March 2019 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes       $ 0