Annual report pursuant to Section 13 and 15(d)

Provision for Income Taxes - Additional Information (Detail)

v3.20.1
Provision for Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Income Taxes Disclosure [Line Items]      
Operating loss carryforwards, limitations on use Net operating loss carryforwards generated after January 1, 2018 may be carried forward indefinitely, subject to the 80% taxable income limitation on the utilization of the carryforwards.    
Research and development credit carry forward $ 710 $ 547  
Open tax year 2014    
Tax, computed at the federal statutory rate 21.00% 21.00% 35.00%
Federal [Member]      
Income Taxes Disclosure [Line Items]      
Operating loss carry forward $ 162,901    
Operating loss carry forwards expiration year 2034    
Research and development credit carry forward $ 505    
Research and development credit expiration year 2036    
State [Member]      
Income Taxes Disclosure [Line Items]      
Operating loss carry forward $ 157,965    
Operating loss carry forwards expiration year 2020    
Research and development credit carry forward $ 260