Revenue from Contracts with Customers (ASC 606) Financial Statement Line Items as Filed and as Adjusted Narrative (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net (loss) income	$ (4,344)	$ (3,293)	$ (6,254)	$ (1,174)	$ 36,738	$ (6,410)
Product sales	39,311			39,312	115,417	113,349
Sales, marketing and support	7,717			7,346	24,700	22,532
Retained earnings (accumulated deficit)	23,021	27,365	(19,971)		23,021			$ (15,397)
Current contract assets	(1,407)	(1,655)	(1,439)		(1,407)			(3,566)
Non-current contract assets	(3,449)	(3,747)	(3,912)		(3,449)			(6,971)
Current contract liabilities	(5,701)	(5,153)	(9,252)		(5,701)			(7,647)
Non-current contract liabilities	(5,194)	(5,198)	(5,263)		(5,194)			(9,070)
Non-current deferred income tax asset	(131)	(820)	(1,692)		(131)			$ (226)
Product
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Product sales	14,808	15,189	13,215	16,367	43,212	46,521
Cost of product sales	10,823	12,649	8,284	$ 9,767	31,756	$ 28,784
Implementation of ASC 606 | Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net (loss) income	(336)	161	(75)		(250)
Sales, marketing and support	20				15
Retained earnings (accumulated deficit)							$ 1,680
Current contract assets							2,132
Non-current contract assets							3,110
Current contract liabilities							2,970
Non-current contract liabilities							4,018
Non-current deferred income tax asset							$ 66
Implementation of ASC 606 | Product | Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Product sales	514	495	341		1,350
Cost of product sales	$ 818	$ 341	$ 431		$ 1,591