COMMITMENTS AND CONTINGENCIES - Additional Lease Information (Details) (USD $)	12 Months Ended							0 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Exton, Pennsylvania	Dec. 31, 2011 Exton, Pennsylvania	Dec. 31, 2010 Exton, Pennsylvania	Nov. 30, 2011 Exton, Pennsylvania	May 31, 2007 Fremont, California	Dec. 31, 2012 Fremont, California	May 31, 2007 Fremont, California Financial Standby Letter of Credit
Operating Leased Assets [Line Items]
Rent expense	$ 4,300,000	$ 5,000,000	$ 4,600,000	$ 900,000
Operating Leases, Future Minimum Payments Due	16,073,000				3,800,000		9,600,000
Payments for (Proceeds from) Loans and Leases				1,700,000
Lease Termination And Other Fees					1,000,000
Sublease revenue				400,000	600,000	1,100,000
Loss Contingency Accrual, at Carrying Value				1,000,000	2,300,000
Term of contract								10 years
Operating lease initial base rent cost								1,400,000
Annual rent increase percentage								3.50%
Operating leases, future minimum payments, at end of lease term	1,500,000								1,500,000
Maximum Payout Under Letter of Credit										$ 1,500,000