XML 50 R40.htm IDEA: XBRL DOCUMENT v3.19.1
Prepaid Expenses and Other Current Assets - Prepaid Expenses and Other Current Assets (Detail) - USD ($)
$ in Thousands
Mar. 31, 2019
Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]    
Prepaid expenses $ 3,853 $ 4,717
Deposits 291 66
Interest receivable on marketable securities 512 717
Total prepaid expenses and other current assets $ 4,656 $ 5,500