Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 179,189	[1]	$ 160,857		$ 126,991
Other comprehensive income (loss)	(650)		958	[2]	110	[2]
Ending balance	182,596		179,189	[1]	160,857
Unrealized Gain (Loss) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(64)		(8)		(16)
Current period other comprehensive income (loss) before reclassifications	58		(56)		8
Reclassification of amounts to earnings	0		0		0
Other comprehensive income (loss)	58		(56)		8
Ending balance	(6)		(64)		(8)
Gain (loss) on Derivative Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	216		(24)		0
Current period other comprehensive income (loss) before reclassifications	165		80		(450)
Reclassification of amounts to earnings	(158)		160		426
Other comprehensive income (loss)	7		240		(24)
Ending balance	223		216		(24)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(411)		(1,185)		(1,311)
Current period other comprehensive income (loss) before reclassifications	(715)		774		126
Reclassification of amounts to earnings	0		0		0
Other comprehensive income (loss)	(715)		774		126
Ending balance	(1,126)		(411)		(1,185)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(259)		(1,217)		(1,327)
Current period other comprehensive income (loss) before reclassifications	(492)		798		(316)
Reclassification of amounts to earnings	(158)		160		426
Other comprehensive income (loss)	(650)		958		110
Ending balance	$ (909)		$ (259)		$ (1,217)

[1] See Note 4.

[2] See Note 4.