Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 150	$ (5,607)	$ 110	$ (10,682)
Other comprehensive income (loss):
Unrealized gain on investments, net of tax	1		1	12
Unrealized gain (loss) on currency translation		(2)		8
Other comprehensive income (loss)	1	(2)	1	20
Comprehensive income (loss)	$ 151	$ (5,609)	$ 111	$ (10,662)