Revenue Recognition - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 48,905	$ 124,442
Deferred revenue, current	17,614	17,620
Right to payment	11,900
Revenue recognized	11,400
Capitalized contract cost, net	1,200
Capitalized contract cost, amortization	400
Capitalized contract cost, impairment loss	$ 1,300
Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings		$ 500