Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v3.7.0.1
Fair Value Measurements (Details) - USD ($)
$ in Thousands
Mar. 31, 2017
Dec. 31, 2016
U.S treasury obligations    
Assets and liabilities measure at fair value on a recurring basis:    
Marketable securities $ 22,495 $ 25,005
Money market funds    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 31,001 58,588
Government agency obligations    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 1,998  
Overnight repurchase agreements    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 15,000  
Recurring    
Assets and liabilities measure at fair value on a recurring basis:    
Total 70,494 83,593
Recurring | U.S treasury obligations    
Assets and liabilities measure at fair value on a recurring basis:    
Marketable securities 22,495 25,005
Recurring | Money market funds    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 31,001 58,588
Recurring | Government agency obligations    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 1,998  
Recurring | Overnight repurchase agreements    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 15,000  
Recurring | Level 1    
Assets and liabilities measure at fair value on a recurring basis:    
Total 55,494 83,593
Recurring | Level 1 | U.S treasury obligations    
Assets and liabilities measure at fair value on a recurring basis:    
Marketable securities 22,495 25,005
Recurring | Level 1 | Money market funds    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 31,001 $ 58,588
Recurring | Level 1 | Government agency obligations    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents 1,998  
Recurring | Level 2    
Assets and liabilities measure at fair value on a recurring basis:    
Total 15,000  
Recurring | Level 2 | Overnight repurchase agreements    
Assets and liabilities measure at fair value on a recurring basis:    
Cash and cash equivalents $ 15,000