Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended			12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Minimum [Member]	Dec. 31, 2012 Minimum [Member]	Mar. 31, 2013 Maximum [Member]	Dec. 31, 2012 Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Vesting period of equity awards			2 years		4 years
Useful life of patents and patent rights				1 year		9 years
Estimated annual effective tax rate	39.00%
Effective tax rate		23.00%
Excess tax benefits from stock-based compensation	$ 709,000	$ 7,611,000
Cash paid for income taxes	3,000,000
Business acquisition deferred tax asset		1,900,000
Income tax benefit from release of valuation allowance	0	10,237,000
Change in deferred tax liability, business acquisition		$ 8,300,000