COMMITMENTS AND CONTINGENCIES - Additional Lease Information (Details) (USD $)	12 Months Ended							0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Exton, Pennsylvania	Dec. 31, 2012 Exton, Pennsylvania	Dec. 31, 2011 Exton, Pennsylvania	Nov. 30, 2011 Exton, Pennsylvania	May 31, 2007 Fremont, California	Dec. 31, 2013 Fremont, California	May 31, 2007 Fremont, California Financial Standby Letter of Credit
Operating Leased Assets [Line Items]
Length of product warranty	12 months
Rent expense	$ 3,929,000	$ 4,260,000	$ 5,040,000	$ 900,000
Sublease revenue				377,000	403,000	597,000
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
Maximum Payout Under Letter of Credit										1,500,000
Operating Leases, Future Minimum Payments Due	11,549,000				3,800,000		9,600,000
Payments for (Proceeds from) Loans and Leases				900,000	1,700,000
Lease Termination And Other Fees					1,000,000
Loss Contingency Accrual, at Carrying Value				$ 700,000	$ 1,000,000