Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense – cost of revenue	$ 10,060	$ 8,824	$ 4,164
Amortization expense – operating expenses	15,550	12,096	8,251
Total amortization expense	$ 25,610	$ 20,920	$ 12,415