CONTINGENCIES (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2011
Product warranty accrual [Roll Forward]
Accrual balance at beginning of year		$ 5,960,000	$ 5,894,000
Accruals for product warranties		6,639,000	3,230,000
Cost of warranty claims		(5,596,000)	(2,977,000)
Accrual balance at end of period	7,003,000	7,003,000	6,147,000
Product warranty information [Abstract]
Standard warranty period	90 days to one year
Extended warranty period	five
Ministry of Revenue Quebec [Member]
Contingencies [Abstract]
Amount assessed and paid related to social taxes on stock-based compensation	1,700,000	1,700,000
Standby Letters of Credit [Member]
Operating Lease Commitments [Abstract]
Letters of Credit Outstanding, Amount	3,700,000	3,700,000
Standby Letters of Credit [Member] | Office Space - Burlington, Massachusetts [Member]
Operating Lease Commitments [Abstract]
Maximum exposure	2,600,000	2,600,000
Aggregate annual reductions to letters of credit at end of years two, three and five of the lease	400,000	400,000
Minimum exposure	1,300,000	1,300,000
Standby Letters of Credit [Member] | Office Space - Daly City, California [Member]
Operating Lease Commitments [Abstract]
Maximum exposure	$ 800,000	$ 800,000