Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash Flows from Operating Activities:
Net income (loss)	$ 7,246,065	$ (2,275,100)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Loss on impairment		1,350,504
Loss on write down / disposal of property and equipment, net	178,175	757,038
Depreciation and amortization	3,395,443	4,117,580
Bond premium amortization	35,812
Provision for doubtful accounts	481	14,580
Provision / write-off of excess and obsolete inventory	197,468	328,870
Provision for warranty	97,226	79,886
Stock-based compensation expense	1,347,662	1,839,924
Litigation judgment expense	(2,200,000)	3,301,243
Deferred income taxes	3,185,099	(1,744,706)
Provision for unrecognized tax benefits	29,967	(1,989)
Change in assets and liabilities:
Accounts receivable	(2,916,419)	3,546,984
Inventory	820,435	1,044,680
Prepaids and other assets	(8,646)	(1,592,862)
Accounts payable and accrued liabilities	397,322	(599,996)
Deferred revenue	1,260,534	(915,816)
Customer deposits	317,882	(95,728)
Net cash provided by operating activities	13,384,506	9,155,092
Cash Flows from Investing Activities:
Purchases of investments	(6,242,033)	(10,775,112)
Proceeds from maturity of investments	6,128,147
Purchases of property and equipment	(602,302)	(659,872)
Purchases of intangible assets	(251,987)	(213,276)
Net cash used in investing activities	(968,175)	(11,648,260)
Cash Flows from Financing Activities:
Repurchase of common stock	(16,138,551)	(12,499,816)
Proceeds from stock options exercised	396,885	3,923
Net cash used in financing activities	(15,741,666)	(12,495,893)
Effect of exchange rate change on cash and cash equivalents	(5,379)	24,225
Net decrease in cash and cash equivalents	(3,330,714)	(14,964,836)
Cash and cash equivalents, beginning of period	21,300,733	42,684,241
Cash and cash equivalents, end of period	17,970,019	27,719,405
Supplemental Disclosure:
Cash paid for income taxes - net	820,361	36,000
Non-Cash Transactions:
Property and equipment purchases in accounts payable	$ 47,955	$ 507,260