Revenue Recognition - Estimated Revenue Expected to be Recognized in Future Related to Performance Obligations (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Product Revenue | Remainder 2018
Revenue, Remaining Performance Obligation	$ 4,308
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Product Revenue | 2019
Revenue, Remaining Performance Obligation	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	2 years
Contract Revenue | Remainder 2018
Revenue, Remaining Performance Obligation	$ 6,358
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Contract Revenue | 2019
Revenue, Remaining Performance Obligation	$ 884
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	2 years