Accumulated Other Comprehensive Income (Loss), Net of Tax (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax:
Balance at beginning of period	$ 23,473
Current period change	(184)
Balance at end of period	21,573
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax:
Balance at beginning of period	(1,818)
Current period change	(188)
Balance at end of period	(2,006)
Unrealized gain (loss) on available-for-sale debt securities
Accumulated Other Comprehensive Income (Loss), Net of Tax:
Balance at beginning of period	(3)
Current period change	4
Balance at end of period	1
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax:
Balance at beginning of period	(1,821)
Balance at end of period	$ (2,005)