Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2013	Dec. 31, 2012
Current Assets:
Cash and cash equivalents	$ 38,580,384	$ 36,126,791
Short-term investments		1,680,958
Accounts and notes receivable, net of allowance of $200,000 as of March 31, 2013 and December 31, 2012	16,806,968	18,101,240
Inventory, net	11,840,390	10,993,209
Prepaid expenses and other current assets	3,912,897	2,754,331
Deferred income tax assets, net	9,395,987	9,395,987
Total current assets	80,536,626	79,052,516
Property and equipment, net	21,202,659	21,952,201
Deferred income tax assets, net	11,783,179	11,605,812
Intangible assets, net	3,287,628	3,317,169
Other assets	258,018	308,553
Total assets	117,068,110	116,236,251
Current Liabilities:
Accounts payable	4,836,520	6,222,904
Accrued liabilities	6,798,624	7,065,085
Current portion of deferred revenue	4,764,557	4,287,305
Customer deposits	385,145	500,018
Current portion of capital lease payable	34,470	33,947
Total current liabilities	16,819,316	18,109,259
Deferred revenue, net of current portion	9,017,567	7,835,767
Liability for unrecorded tax benefits	2,960,396	2,902,896
Long-term portion of capital lease payable	94,468	103,283
Total liabilities	28,891,747	28,951,205
Commitments and Contingencies
Stockholders' Equity:
Preferred stock, $0.00001 par value per share; 25 million shares authorized; no shares at March 31, 2013 and December 31, 2012
Common stock, $0.00001 par value per share; 200 million shares authorized; 52,410,534 and 52,770,392 shares issued and outstanding at March 31, 2013 and December 31, 2012, respectively	665	661
Additional paid-in capital	114,623,636	111,661,393
Treasury stock at cost,14,066,655 and 13,363,789 shares at March 31, 2013 and December 31, 2012, respectively	(72,553,558)	(67,203,043)
Retained earnings	46,180,888	42,883,067
Accumulated other comprehensive loss	(75,268)	(57,032)
Total stockholders' equity	88,176,363	87,285,046
Total liabilities and stockholders' equity	$ 117,068,110	$ 116,236,251