INCOME TAXES - Significant components of the deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carryforwards	$ 49,313	$ 61,308
Tax credit carryforwards	60,524	56,575
Deferred revenue	1,036	1,849
Capitalized research and development costs	497	245
Intangibles	15,380	17,474
Share-based compensation	5,049	4,371
Accrued compensation	5,472	4,625
Accrued warranty	474	347
Inventory reserves	6,501	7,224
Reserves and other	8,239	7,178
Depreciation and amortization	5,202	6,080
Other, net	4,255	9,463
Total deferred tax assets	161,942	176,739
Valuation allowance for deferred tax assets	(126,252)	(137,957)
Net deferred tax assets	35,690	38,782
Net deferred tax liabilities:
Acquired intangible assets	(29,587)	(33,735)
Acquired tangible assets	0	(78)
Cancellation of debt	(5,854)	(7,701)
Foreign earnings	(4,520)	(2,734)
Other, net	(1,457)	(1,471)
Total deferred tax liabilities	(41,418)	(45,719)
Net deferred tax liabilities	$ (5,728)	$ (6,937)