Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Allowances on accounts receivable	$ 119,530	$ 276,302
Accumulated depreciation on property and equipment	16,867,911	16,022,230
Series A redeemable convertible preferred stock, par value	$ 0.001	$ 0.001
Series A redeemable convertible preferred stock, shares authorized	2,000,000us-gaap_TemporaryEquitySharesAuthorized	2,000,000us-gaap_TemporaryEquitySharesAuthorized
Series A redeemable convertible preferred stock, shares issued	900,000us-gaap_TemporaryEquitySharesIssued	900,000us-gaap_TemporaryEquitySharesIssued
Series A redeemable convertible preferred stock, shares outstanding	900,000	900,000
Series A redeemable convertible preferred stock, redemption value	$ 9,000,000	$ 9,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000us-gaap_CommonStockSharesAuthorized	100,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	56,360,222us-gaap_CommonStockSharesIssued	56,036,972us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	40,924,313us-gaap_CommonStockSharesOutstanding	48,031,737us-gaap_CommonStockSharesOutstanding
Common Stock, held in treasury, shares	15,435,909us-gaap_TreasuryStockShares	8,005,235us-gaap_TreasuryStockShares

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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