Quarterly report pursuant to Section 13 or 15(d)

Cash Equivalents and Marketable Securities (Details)

v3.19.2
Cash Equivalents and Marketable Securities (Details)
 6 Months Ended
Jun. 30, 2019
USD ($)
item
Dec. 31, 2018
USD ($)
Cash Equivalents and Marketable Securities    
Marketable Securities, Amortized Cost $ 121,714,000 $ 99,682,000
Marketable Securities, Unrealized Gains 4,000  
Marketable Securities, Unrealized Losses   (3,000)
Marketable Securities, Fair Value 121,718,000 99,679,000
Realized gains (losses) $ 0  
Number of investments adjusted for other-than-temporary declines in fair value | item 0  
Number of Unrealized loss positions | item 0  
U.S treasury obligations    
Cash Equivalents and Marketable Securities    
Marketable Securities, Amortized Cost $ 19,974,000 49,796,000
Marketable Securities, Unrealized Gains 4,000  
Marketable Securities, Unrealized Losses   (3,000)
Marketable Securities, Fair Value 19,978,000 49,793,000
Cash and money market funds    
Cash Equivalents and Marketable Securities    
Cash Equivalents, Amortized Cost 20,240,000 34,886,000
Cash Equivalents, Fair value 20,240,000 34,886,000
Overnight repurchase agreements    
Cash Equivalents and Marketable Securities    
Cash Equivalents, Amortized Cost 81,500,000 15,000,000
Cash Equivalents, Fair value $ 81,500,000 $ 15,000,000