Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Components of Deferred Tax Assets
Deferred tax assets - non current	$ 26,277	$ 30,039
Deferred tax liabilities - non current	(8,757)	0
Net operating losses	45,041	32,088
Accrued liabilities	25,384	26,355
Deferred compensation	11,675	14,273
Accrued compensation	6,854	6,527
Deferred revenue	2,780	4,564
Deferred rent	506	2,469
Tax credits	6,629	4,524
Equity awards	4,076	4,296
Other, net	453	1,260
Valuation allowance	(22,577)	(17,312)
Total deferred tax assets	80,821	79,044
Intangible assets	(30,084)	(40,935)
Capitalized transaction costs	(17,955)	(5,945)
Depreciation	(15,262)	(2,125)
Total deferred tax liabilities	(63,301)	(49,005)
Total net deferred tax assets	$ 17,520	$ 30,039