Non-Recurring Charges (Details) (USD $)	12 Months Ended							0 Months Ended
	Dec. 31, 2013 item	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Non-recurring charges	Dec. 31, 2013 Proxy contest costs	Dec. 31, 2013 Employee severance costs	Dec. 31, 2013 Facilities-related costs	Jul. 18, 2013 Nonrecurring transaction Proxy Related Lawsuits
Non-recurring charges
Reimbursement of expenses incurred in connection with proxy solicitation								$ 2,900,000
Number of employees reduced	20
Number of employees reduced (as a percent)	17.00%
Activity for the proxy contest and cost reduction plan
Charges	18,619,000				8,862,000	8,546,000	1,211,000
Payments	(11,088,000)				(8,862,000)	(2,037,000)	(189,000)
Balance of accrued employees severance and facilities-related costs accrued at the end of the period	7,531,000					6,509,000	1,022,000
Lease expiration date							May 31, 2020
Additional disclosures
Non-cash share-based compensation expense	32,397,000	15,938,000	7,353,000	14,072,000
Non-recurring charges	32,691,000			32,700,000
Accrued severance and facilities-related costs, Current	4,577,000
Accrued severance and facilities-related costs, Non-current	3,000,000
Restructuring accrual anticipated to be paid out
2014	4,705,000
2015	2,581,000
2016	80,000
2017	55,000
2018	46,000
Thereafter	64,000
Total	$ 7,531,000					$ 6,509,000	$ 1,022,000