Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail)

v3.20.1
Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($)
$ in Thousands
Dec. 31, 2019
Dec. 31, 2018
Assets    
Total assets $ 16,714 $ 14,654
Cash [Member]    
Assets    
Total assets 949 1,070
Money market securities (cash equivalents) [Member]    
Assets    
Total assets 15,715 8,445
Restricted cash [Member]    
Assets    
Total assets 50 50
Corporate bonds and commercial paper [Member]    
Assets    
Total assets   5,089
Level 1 [Member]    
Assets    
Total assets 16,714 9,565
Level 1 [Member] | Cash [Member]    
Assets    
Total assets 949 1,070
Level 1 [Member] | Money market securities (cash equivalents) [Member]    
Assets    
Total assets 15,715 8,445
Level 1 [Member] | Restricted cash [Member]    
Assets    
Total assets $ 50 50
Level 2 [Member]    
Assets    
Total assets   5,089
Level 2 [Member] | Corporate bonds and commercial paper [Member]    
Assets    
Total assets   $ 5,089