Quarterly report pursuant to Section 13 or 15(d)

Cash, Cash Equivalents and Investments - Cash Equivalents and Investments (Details)

v3.19.1
Cash, Cash Equivalents and Investments - Cash Equivalents and Investments (Details)
$ in Thousands
 3 Months Ended
Mar. 31, 2019
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Amortized Cost $ 58,494
Unrealized gains 191
Unrealized losses 0
Fair Value 58,685
U.S. treasuries  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Amortized Cost 12,500
Unrealized gains 30
Unrealized losses 0
Fair Value $ 12,530
U.S. treasuries | Minimum  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contractual maturity 60 days
U.S. treasuries | Maximum  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contractual maturity 165 days
Asset-backed securities  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Amortized Cost $ 7,207
Unrealized gains 23
Unrealized losses 0
Fair Value $ 7,230
Asset-backed securities | Minimum  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contractual maturity 106 days
Asset-backed securities | Maximum  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contractual maturity 169 days
Corporate bonds  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Amortized Cost $ 38,787
Unrealized gains 138
Unrealized losses 0
Fair Value $ 38,925
Corporate bonds | Minimum  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contractual maturity 1 day
Corporate bonds | Maximum  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Contractual maturity 194 days