Schedule of Difference Between Effective and Statutory (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
U.S. federal income tax rate	35.00%	35.00%	35.00%
State taxes	3.40%	3.50%	2.80%
Nondeductible stock-based compensation	0.80%	1.30%	0.80%
U.S. federal and state research and development credits	(3.50%)	(0.60%)	(2.40%)
Change in state tax rates	0.00%	(0.40%)	(0.10%)
Foreign earnings	(2.60%)	(3.50%)	(2.20%)
Expiration of capital loss carryforward	0.00%	0.00%	2.10%
Disallowed officer compensation	0.10%	0.60%	0.00%
Domestic production activities deduction	(4.30%)	0.00%	0.00%
Other	0.50%	0.70%	0.90%
Change in the deferred tax asset valuation allowance	0.60%	0.00%	(2.30%)
Effective income tax rate	30.00%	36.60%	34.60%