Annual report pursuant to Section 13 and 15(d)

Stock and Employee Benefit Plans - Narrative (Details)

v3.20.1
Stock and Employee Benefit Plans - Narrative (Details)
 1 Months Ended 12 Months Ended
Dec. 31, 2018
USD ($)
Dec. 31, 2019
USD ($)
purchase_period
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Defined Benefit Plan Disclosure [Line Items]      
Issuance of common stock resulting from purchase of employee stock purchase plan shares (shares)   113,112  
Stock-based compensation expense | $   $ 5,374,000 $ 4,943,000
Unrecognized compensation costs related to nonvested awards | $   $ 9,300,000  
Weighted-average compensation cost recognition period   2 years 5 months 15 days  
Purchases during period | $   $ 369,000  
Research and development      
Defined Benefit Plan Disclosure [Line Items]      
Stock-based compensation expense | $   2,446,000 1,984,000
General and administrative      
Defined Benefit Plan Disclosure [Line Items]      
Stock-based compensation expense | $   $ 2,928,000 $ 2,959,000
2016 Stock Plan      
Defined Benefit Plan Disclosure [Line Items]      
Stock available for future grant (shares)   654,000  
Common stock authorized for issuance (shares)   3,000,000  
Maximum term of stock options   10 years  
Number of options granted (shares)   2,489,269 1,881,660
Weighted-average fair value (USD per share) | $ / shares   $ 2.31 $ 5.04
2018 Stock Plan      
Defined Benefit Plan Disclosure [Line Items]      
Stock available for future grant (shares)   2,912,721  
Stock issuable under plan (shares)   5,750,000  
Common stock authorized for issuance (shares)   2,750,000  
Executive Officers and Senior Leadership      
Defined Benefit Plan Disclosure [Line Items]      
Unrecognized compensation costs related to nonvested awards | $   $ 1,200,000  
Employee Stock      
Defined Benefit Plan Disclosure [Line Items]      
Common stock authorized for issuance (shares)   500,000  
Discount from market price (as a percent)   85.00%  
Number of purchase periods | purchase_period   2  
Term of purchase period   6 months  
Purchases during period | $ $ 0