Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets:
Accruals and allowances	$ 20,765	$ 16,629
Net operating loss carryforwards	1,673	50
Stock-based compensation	5,734	5,634
Deferred rent	1,296	1,977
Deferred revenue	1,100	1,459
Tax credit carryforwards	1,661	974
Acquired intangibles	31,902	15,598
Depreciation and amortization	866	904
Total deferred tax assets	64,997	43,225
Deferred Tax Liabilities:
Other	(706)	(362)
Total deferred tax liabilities	(706)	(362)
Valuation allowance	(6,734)	(4,570)
Net deferred tax assets	57,557	38,293
Valuation allowance, net of federal tax	$ 5,400	$ 3,600