Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities (Details)

v3.20.1
Marketable Securities (Details)
$ in Thousands
Mar. 31, 2020
USD ($)
security
Dec. 31, 2019
USD ($)
security
Schedule of Available-for-sale Securities [Line Items]    
Fair market value of investments in an unrealized loss position $ 90,900 $ 2,000
Number of debt securities | security 36 1
Number of available-for-sale securities in an unrealized loss position for more than one year | security 0  
Cash equivalents    
Schedule of Available-for-sale Securities [Line Items]    
Amortized cost $ 10,338  
Gross unrealized gains 2  
Gross unrealized losses (3)  
Aggregate estimated fair value 10,337  
Debt Securities    
Schedule of Available-for-sale Securities [Line Items]    
Amortized cost 110,548  
Gross unrealized gains 25  
Gross unrealized losses (573)  
Aggregate estimated fair value 110,000  
Corporate Debt Securities Maturity Period Less Than Three Months | Cash equivalents    
Schedule of Available-for-sale Securities [Line Items]    
Amortized cost 10,338  
Gross unrealized gains 2  
Gross unrealized losses (3)  
Aggregate estimated fair value 10,337  
Corporate Debt Securities Maturity Period Less Than Three Months | Debt Securities    
Schedule of Available-for-sale Securities [Line Items]    
Amortized cost 13,684  
Gross unrealized gains 7  
Gross unrealized losses (17)  
Aggregate estimated fair value 13,674  
Corporate Debt Securities Maturity Period Three Months To One Year | Debt Securities    
Schedule of Available-for-sale Securities [Line Items]    
Amortized cost 76,635  
Gross unrealized gains 8  
Gross unrealized losses (455)  
Aggregate estimated fair value 76,188  
Treasury Bills Maturity Period Three Months To One Year | Debt Securities    
Schedule of Available-for-sale Securities [Line Items]    
Amortized cost 1,991  
Gross unrealized gains 7  
Aggregate estimated fair value 1,998  
Corporate Debt Securities Maturity Period One Year To Two Years | Debt Securities    
Schedule of Available-for-sale Securities [Line Items]    
Amortized cost 18,238  
Gross unrealized gains 3  
Gross unrealized losses (101)  
Aggregate estimated fair value $ 18,140