Segment Data - Summary of Operational Information Relative to the Company's Reportable Segments (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Product sales	$ 31,842,404	$ 28,095,855	$ 62,025,082	$ 53,625,660
Service revenue	333,393	126,588	584,367	238,175
Net sales	32,175,797	28,222,443	62,609,449	53,863,835
Cost of products sold	11,766,609	10,520,810	23,171,122	19,926,078
Cost of services delivered	666,825	1,199,260	1,244,960	2,194,125
Gross margin	19,742,363	16,502,373	38,193,367	31,743,632
Sales, general & administrative	10,940,085	8,404,611	22,122,025	17,258,633
Research & development	1,992,064	2,038,830	4,004,620	4,171,050
Litigation judgment				(2,200,000)
Income (loss) from operations	6,810,214	6,058,932	12,066,722	12,513,949
Purchases of property and equipment	455,906	302,572	838,995	602,302
Purchases of intangible assets	98,680	129,809	202,193	251,987
Depreciation and amortization	1,529,507	1,728,933	2,948,266	3,395,443
CEW [Member]
Segment Reporting Information [Line Items]
Product sales	30,272,853	26,931,727	58,275,475	51,689,401
Service revenue
Net sales	30,272,853	26,931,727	58,275,475	51,689,401
Cost of products sold	10,410,910	9,783,886	20,627,577	18,395,306
Cost of services delivered
Gross margin	19,861,943	17,147,841	37,647,898	33,294,095
Sales, general & administrative	9,417,473	7,668,654	19,491,138	15,755,151
Research & development	977,508	922,084	1,966,189	1,762,436
Litigation judgment				(2,200,000)
Income (loss) from operations	9,466,962	8,557,103	16,190,571	17,976,508
Purchases of property and equipment	344,098	181,847	597,931	313,291
Purchases of intangible assets	90,074	129,809	193,587	251,987
Depreciation and amortization	973,736	1,088,838	1,972,684	2,282,454
Video [Member]
Segment Reporting Information [Line Items]
Product sales	1,569,551	1,164,128	3,749,607	1,936,259
Service revenue	333,393	126,588	584,367	238,175
Net sales	1,902,944	1,290,716	4,333,974	2,174,434
Cost of products sold	1,355,699	736,924	2,543,545	1,530,772
Cost of services delivered	666,825	1,199,260	1,244,960	2,194,125
Gross margin	(119,580)	(645,468)	545,469	(1,550,463)
Sales, general & administrative	1,522,612	735,957	2,630,887	1,503,482
Research & development	1,014,556	1,116,746	2,038,431	2,408,614
Litigation judgment
Income (loss) from operations	(2,656,748)	(2,498,171)	(4,123,849)	(5,462,559)
Purchases of property and equipment	111,808	120,725	241,064	289,011
Purchases of intangible assets	8,606		8,606
Depreciation and amortization	$ 555,771	$ 640,095	$ 975,582	$ 1,112,989