Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member]
$ in Thousands
Mar. 31, 2019
USD ($)
Assets  
Total assets $ 9,715
Cash [Member]  
Assets  
Total assets 2,187
Money market securities (cash equivalents) [Member]  
Assets  
Total assets 5,133
Restricted cash [Member]  
Assets  
Total assets 50
Corporate bonds and commercial paper (short term investments) [Member]  
Assets  
Total assets 2,345
Level 1 [Member]  
Assets  
Total assets 7,370
Level 1 [Member] | Cash [Member]  
Assets  
Total assets 2,187
Level 1 [Member] | Money market securities (cash equivalents) [Member]  
Assets  
Total assets 5,133
Level 1 [Member] | Restricted cash [Member]  
Assets  
Total assets 50
Level 2 [Member]  
Assets  
Total assets 2,345
Level 2 [Member] | Corporate bonds and commercial paper (short term investments) [Member]  
Assets  
Total assets $ 2,345