Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Details)

v3.10.0.1
Fair Value Measurements (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Assets measured at fair value on a recurring basis:    
Marketable securities $ 99,679 $ 72,049
U.S treasury obligations    
Assets measured at fair value on a recurring basis:    
Marketable securities 49,793 39,844
Cash and money market funds    
Assets measured at fair value on a recurring basis:    
Cash and cash equivalents 34,886 17,205
Overnight repurchase agreements    
Assets measured at fair value on a recurring basis:    
Cash and cash equivalents 15,000 15,000
Recurring    
Assets measured at fair value on a recurring basis:    
Total 99,679 72,049
Recurring | U.S treasury obligations    
Assets measured at fair value on a recurring basis:    
Marketable securities 49,793 39,844
Recurring | Cash and money market funds    
Assets measured at fair value on a recurring basis:    
Cash and cash equivalents 34,886 17,205
Recurring | Overnight repurchase agreements    
Assets measured at fair value on a recurring basis:    
Cash and cash equivalents 15,000 15,000
Recurring | Level 1    
Assets measured at fair value on a recurring basis:    
Total 84,679 57,049
Recurring | Level 1 | U.S treasury obligations    
Assets measured at fair value on a recurring basis:    
Marketable securities 49,793 39,844
Recurring | Level 1 | Cash and money market funds    
Assets measured at fair value on a recurring basis:    
Cash and cash equivalents 34,886 17,205
Recurring | Level 2    
Assets measured at fair value on a recurring basis:    
Total 15,000 15,000
Recurring | Level 2 | Overnight repurchase agreements    
Assets measured at fair value on a recurring basis:    
Cash and cash equivalents $ 15,000 $ 15,000