Income Taxes (Details) (USD $)	9 Months Ended
	Sep. 30, 2013
Activity relating to the Company's unrecognized tax benefits
Balance at the beginning of the period	$ 12,148,000
Gross increases related to current period tax positions	1,987,000
Balance at the end of the period	14,135,000
Unrecognized tax benefits relating to federal research credits, California research credits, Massachusetts research credits and California enterprise zone credits	2,000,000
Portion of unrecognized tax benefits, if recognized would decrease the entity's tax provision and increase net income	11,700,000
Provision made for undistributed earnings of foreign subsidiaries	0
Undistributed earnings for non-U.S. subsidiaries which are deemed to be permanently reinvested	$ 17,300,000