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 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 32,320 $ 6,333 $ 22,758 $ 12,895
Beginning balance (in shares)     19,663,698  
Net (loss) income (605) 909 $ (3,623) (12,474)
Stock-based compensation expense 588 399 1,528 1,220
Common stock issued through employee stock purchase and stock option plans       28
Common stock issued through employee stock purchase 13 9 22  
Common stock issued, net of expenses 5,301 1,909 8,713 4,578
Common stock issued for commitment shares       602
Common stock issued for vested restricted stock units (3) (1) (3) (75)
Vested Loan Agreement warrants     766  
Ending balance $ 37,614 9,558 $ 37,614 9,558
Ending balance (in shares) 23,885,570   23,885,570  
April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     $ 7,453 2,784
Common Stock        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 26 $ 10 $ 20 $ 10
Beginning balance (in shares) 23,147,552 10,478,927 19,663,698 9,741,372
Net (loss) income $ 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 through employee stock purchase $ 0 $ 0 $ 0  
Common stock issued through employee stock purchase (in shares) 2,759 2,284 4,943  
Common stock issued, net of expenses $ 1 $ 0 $ 6 $ 0
Common stock issued, net of expenses (in shares) 733,937 315,939 3,250,739 647,504
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) 1,322 969 7,110 17,220
Vested Loan Agreement warrants     $ 0  
Ending balance $ 27 $ 10 $ 27 $ 10
Ending balance (in shares) 23,885,570 10,798,119 23,885,570 10,798,119
Common Stock | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     $ 1 $ 0
Common stock issued for conversion of Notes (in shares)     959,080 316,461
Additional Paid-in Capital        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance $ 361,925 $ 291,134 $ 349,351 $ 284,313
Net (loss) income 0 0 0 0
Stock-based compensation expense 588 399 1,528 1,220
Common stock issued through employee stock purchase and stock option plans       28
Common stock issued through employee stock purchase 13 9 22  
Common stock issued, net of expenses 5,300 1,909 8,707 4,578
Common stock issued for commitment shares       602
Common stock issued for vested restricted stock units (3) (1) (3) (75)
Vested Loan Agreement warrants     766  
Ending balance 367,823 293,450 367,823 293,450
Additional Paid-in Capital | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     7,452 2,784
Accumulated Deficit        
Common Stock Outstanding Roll Forward [Roll Forward]        
Beginning balance (329,631) (284,811) (326,613) (271,428)
Net (loss) income (605) 909 (3,623) (12,474)
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 0 0  
Common stock issued, net of expenses 0 0 0 0
Common stock issued for commitment shares       0
Common stock issued for vested restricted stock units 0 0 0 0
Vested Loan Agreement warrants     0  
Ending balance $ (330,236) $ (283,902) (330,236) (283,902)
Accumulated Deficit | April 2020 Notes        
Common Stock Outstanding Roll Forward [Roll Forward]        
Common stock issued for conversion of Notes     $ 0 $ 0