Schedule II - Valuation and Qualifying Accounts (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred Recovery Cost Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year			$ 2,557,149
Charged (credited) to other accounts	0	0	0
Deductions			2,557,149
Inventory Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	371,332	367,558	392,203
Charged (credited) to expenses		3,774
Charged (credited) to other accounts	0	0	0
Deductions			24,645
Balance at ending of year	371,332	371,332	367,558
Accounts Receivable Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	5,131,593	4,820,593	6,390,593
Charged (credited) to expenses		500,000
Charged (credited) to other accounts	0	0	0
Deductions	500,000	189,000	1,570,000
Balance at ending of year	$ 4,631,593	$ 5,131,593	$ 4,820,593

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

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Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

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