Quarterly report pursuant to Section 13 or 15(d)

Debt - Schedule of Activity and Balances Associated with the Notes and Related Deferred Transaction Costs (Details)

v3.10.0.1
Debt - Schedule of Activity and Balances Associated with the Notes and Related Deferred Transaction Costs (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Sep. 30, 2018
Sep. 30, 2017
Convertible Notes And Deferred Transaction Costs[Roll forward]          
Less: amortization for the three months ended March 31, 2018       $ (1,222) $ (1,014)
Notes Balance, end of period $ 100,000     100,000  
Convertible Senior Notes Due 2019          
Convertible Notes And Deferred Transaction Costs[Roll forward]          
Notes Balance, beginning of period 18,603 $ 18,603 $ 18,603 18,603  
Deferred Debt Costs, beginning of period 946 1,123 1,301 1,301  
Notes, net of Deferred Debt Costs, beginning of period 17,657 17,480 17,302 17,302  
Less: amortization for the three months ended March 31, 2018 (177) (177) (178)    
Notes Balance, end of period 18,603 18,603 18,603 18,603  
Deferred Debt Costs, end of period 769 946 1,123 769  
Notes, net of Deferred Debt Costs, end of period $ 17,834 $ 17,657 $ 17,480 $ 17,834