Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Fair Value Measurements - Summary of Cash, Cash Equivalents and Short-Term Investments (Detail) - USD ($)
$ in Thousands
Mar. 31, 2019
Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash, amortized cost and estimated fair value $ 2,187  
Cash and cash equivalents, amortized cost and estimated fair value 7,320 $ 9,515
Restricted cash, amortized cost and estimated fair value 50  
Short-term investments, amortized cost and estimated fair value 2,345 $ 5,089
Money market securities [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Cash equivalents, amortized cost and estimated fair value 5,133  
Restricted cash, amortized cost and estimated fair value 50  
Corporate bonds and commercial paper [Member]    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Short-term investments, amortized cost and estimated fair value $ 2,345