Revenue Recognition - Remaining Obligations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Deferred revenue, current portion	$ 1,443	$ 1,420
Amounts included in deferred revenue at beginning of the period	(941)
Evercord
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Deferred revenue, noncurrent	1,000
Qiagen
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 40,000