Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Schedule of Marketable Available-for-Sale Securities (Detail)

v3.7.0.1
Summary of Significant Accounting Policies - Schedule of Marketable Available-for-Sale Securities (Detail) - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost $ 7,218 $ 6,500
Gross Unrealized Gains 0 0
Gross Unrealized Losses (1) (1)
Estimated Fair Value 7,217 6,499
Corporate Debt Securities [Member] | Marketable Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost 2,201 2,205
Gross Unrealized Gains 0 0
Gross Unrealized Losses (1) (1)
Estimated Fair Value 2,200 2,204
Asset-backed Securities [Member] | Marketable Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost 1,370  
Gross Unrealized Gains 0  
Estimated Fair Value 1,370  
Commercial Paper [Member] | Marketable Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost 3,647 4,295
Gross Unrealized Gains 0 0
Estimated Fair Value $ 3,647 $ 4,295