Income Taxes (Reconciliation of Statutory Federal Income Tax Rate to Effective Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. federal taxes at statutory rate	$ 24,502	$ 19,354	$ 17,954
Changes in valuation allowance	0	0	(119,765)
Federal tax rate change impact to change in valuation allowance	0	0	33,233
R&D and other credits	(4,504)	(2,178)	(1,199)
State income taxes	3,819	1,975	(2,955)
Non-deductible compensation	657	394	33
Stock-based compensation	(2,107)	(3,165)	(3,826)
Other	128	363	209
Total	$ 22,495	$ 16,743	$ (76,316)