Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Summary of Cash, Cash Equivalents and Short-Term Investments (Detail)

v3.10.0.1
Fair Value Measurements - Summary of Cash, Cash Equivalents and Short-Term Investments (Detail) - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash, amortized cost and estimated fair value $ 1,083  
Cash and cash equivalents, amortized cost and estimated fair value 15,280 $ 5,284
Restricted cash, amortized cost and estimated fair value 50  
Money market securities [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash equivalents, amortized cost and estimated fair value 14,197  
Restricted cash, amortized cost and estimated fair value $ 50