Historical Operating Results of Schneider Power Classified as Discontinued Operations (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Revenue:
Net product sales	$ 3,505,095		$ 3,545,741
Costs and expenses:
Cost of product sales	2,603,876		2,506,879
Research and development	2,354,500		3,941,269
Selling, general and administrative	3,328,607		3,492,491
Total operating costs and expenses	8,286,983		9,940,639
Operating Income (Loss)	(3,879,726)		(4,035,335)
Interest expense, net	(1,395,433)		(3,245,227)
Goodwill impairment	1,736,208		0
Segment, Discontinued Operations | Schneider Power
Revenue:
Net product sales	857,958		88,552
Costs and expenses:
Cost of product sales	168,967		28,940
Research and development	16,872		45,268
Selling, general and administrative	271,807		273,490
Amortization of long-lived assets	0		37,046
Impairment of goodwill and intangible assets of discontinued operations	1,736,208	[1]	0	[1]
Total operating costs and expenses	2,193,854		384,744
Operating Income (Loss)	(1,335,896)		(296,192)
Interest expense, net	(372,267)		(127,096)
Loss from discontinued operations before income taxes	(1,708,163)		(423,288)
Goodwill impairment	1,000,000
Intangible impairment	$ 700,000

[1] We measure each disposal group of Schneider Power at the lower of its carrying amount or fair value less costs to sell. The fair value measurements are based on Level 3 inputs such as market conditions and pending agreements to sell the assets. Based on an assessment that we updated as of March 31, 2013, we determined that the fair value of goodwill and intangible assets of certain disposal groups were above their fair values, net of selling costs. As a result, we recognized impairment charges of $1.7 million during the first quarter of 2013, of which $1.0 million is related to goodwill and $0.7 million is related to intangible assets.