Taxes - Constituents of Deferred Tax Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Current deferred tax assets:
Inventory and revenue related	$ 5,614,000	$ 4,303,000
Bonuses, commissions, and other compensation	1,377,000	1,280,000
Other	1,292,000	1,093,000
Gross current deferred tax assets	8,283,000	6,676,000
Valuation allowance	(672,000)	(307,000)
Net current deferred tax assets	7,611,000	6,369,000
Noncurrent deferred tax assets:
Stock-based compensation expense	7,488,000	7,242,000
Federal and state tax credit carryforwards	5,418,000	9,747,000
Depreciation	1,831,000	1,819,000
Acquired completed technologies and other intangible assets	835,000	1,119,000
Unrealized investment gains and losses	601,000	1,075,000
Correlative tax relief and deferred interest related to reserves	252,000	520,000
Capital loss carryforward		373,000
Acquired in-process technology		90,000
Other	1,178,000	1,960,000
Gross noncurrent deferred tax assets	17,603,000	23,945,000
Noncurrent deferred tax liabilities:
Nondeductible intangible assets	(3,662,000)	(4,945,000)
Other	(548,000)	(2,171,000)
Gross noncurrent deferred tax liabilities	(4,210,000)	(7,116,000)
Valuation allowance	(1,086,000)	(1,182,000)
Net noncurrent deferred tax assets	$ 12,307,000	$ 15,647,000