Summary of Significant Accounting Policies (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 30,387	$ 60,297	$ 36,200	$ 46,513
Change in period	(402)	1,906	218	974
Ending balance	27,301	49,169	27,301	49,169
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(1,470)
Change in period			218
Ending balance	(1,252)		(1,252)
Change in unrealized gain (loss) on available-for-sale securities, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			0
Change in period			0
Ending balance	0		0
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(850)	(4,168)	(1,470)	(3,236)
Change in period	(402)	1,906	218	974
Ending balance	$ (1,252)	$ (2,262)	$ (1,252)	$ (2,262)