Quarterly report pursuant to Section 13 or 15(d)

Fair Value - Schedule of Fair Value of Financial Assets and Liabilities Inputs (Details)

v3.7.0.1
Fair Value - Schedule of Fair Value of Financial Assets and Liabilities Inputs (Details) - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
Assets:    
Total assets measured at fair value $ 18,056 $ 43,361
Corporate debt securities    
Assets:    
Total assets measured at fair value 18,056 43,361
Quoted Prices in Active Markets for Identical Instruments (Level 1)    
Assets:    
Total assets measured at fair value 0 0
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Corporate debt securities    
Assets:    
Total assets measured at fair value 0 0
Significant Other Observable Inputs (Level 2)    
Assets:    
Total assets measured at fair value 18,056 43,361
Significant Other Observable Inputs (Level 2) | Corporate debt securities    
Assets:    
Total assets measured at fair value $ 18,056 $ 43,361