Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.2
Stockholders' Equity - Summary of Common Stock Shares Activity (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 25,924 $ 6,455 $ 22,758 $ 12,895
Beginning balance (in shares)     19,663,698  
Net income (loss) 1,658 (6,381) $ (3,018) (13,383)
Stock-based compensation expense 542 410 940 821
Common stock issued through employee stock purchase and stock option plans       18
Common stock issued through employee stock purchase     9  
Common stock issued for exercise of stock options   0    
Common stock issued, net of expenses 3,415 2,463 3,412 2,669
Common stock issued for Commitment Shares   602   602
Common stock issued for vested restricted stock units 15 0 0 (73)
Vested Loan Agreement warrants 766   766  
Ending balance $ 32,320 6,333 $ 32,320 6,333
Ending balance (in shares) 23,147,552   23,147,552  
April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes   2,784 $ 7,453 2,784
Common Stock        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 21 $ 10 $ 20 $ 10
Beginning balance (in shares) 20,625,637 9,787,604 19,663,698 9,741,372
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)       2,368
Common stock issued through employee stock purchase     $ 0  
Common stock issued through employee stock purchase (in shares)     2,184  
Common stock issued for exercise of stock options   $ 0    
Common stock issued for exercise of stock options (in shares)   151    
Common stock issued, net of expenses $ 5 $ 0 $ 5 $ 0
Common stock issued, net of expenses (in shares) 2,516,802 303,038 2,516,802 331,565
Common stock issued for Commitment Shares   $ 0   $ 0
Common stock issued for Commitment Shares (in shares)   70,910   70,910
Common stock issued for vested restricted stock units $ 0 $ 0 $ 0 $ 0
Common stock issued for vested restricted stock units (in shares) 5,113 762 5,788 16,250
Vested Loan Agreement warrants $ 0   $ 0  
Ending balance $ 26 $ 10 $ 26 $ 10
Ending balance (in shares) 23,147,552 10,478,927 23,147,552 10,478,927
Common Stock | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes   $ 0 $ 1 $ 0
Common stock issued for conversion of Notes (in shares)   316,461 959,080 316,461
Additional Paid-in Capital        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 357,192 $ 284,875 $ 349,351 $ 284,313
Net income (loss) 0 0 0 0
Stock-based compensation expense 542 410 940 821
Common stock issued through employee stock purchase and stock option plans       18
Common stock issued through employee stock purchase     9  
Common stock issued for exercise of stock options   0    
Common stock issued, net of expenses 3,410 2,463 3,407 2,669
Common stock issued for Commitment Shares   602   602
Common stock issued for vested restricted stock units 15 0 0 (73)
Vested Loan Agreement warrants 766   766  
Ending balance 361,925 291,134 361,925 291,134
Additional Paid-in Capital | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes   2,784 7,452 2,784
Accumulated Deficit        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance (331,289) (278,430) (326,613) (271,428)
Net income (loss) 1,658 (6,381) (3,018) (13,383)
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     0  
Common stock issued for exercise of stock options   0    
Common stock issued, net of expenses 0 0 0 0
Common stock issued for Commitment Shares   0   0
Common stock issued for vested restricted stock units 0 0 0 0
Vested Loan Agreement warrants 0   0  
Ending balance $ (329,631) (284,811) (329,631) (284,811)
Accumulated Deficit | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes   $ 0 $ 0 $ 0