Condensed Consolidated Statements of Cash Flows (unaudited) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income	$ 3,068,002	$ 1,912,119
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	1,202,208	986,913
Stock-based compensation expense	422,959	320,510
Deferred income taxes	(139,747)	(82,206)
Provision for inventory	258,195	49,558
Tax benefit from exercise of stock options	(64,642)	(394,076)
Changes in operating assets and liabilities:
Accounts receivable	6,373,839	358,471
Inventories	(1,969,179)	(1,769,606)
Prepaid expenses, other current and long-term assets	705,078	(324,152)
Long-term deposits and other	8,499	8,499
Accounts payable	1,354,318	(476,940)
Accrued expenses	(2,351,133)	(1,341,407)
Deferred revenue	(725,067)	(716,667)
Income taxes payable	(1,834,739)	(215,156)
Other long-term liabilities	(239,737)	(5,509)
Net cash provided by (used in) operating activities	6,068,854	(1,689,649)
Cash flows from investing activities:
Purchase of property and equipment, net	(35,802)	(224,059)
Proceeds from sale of property and equipment	135,607
Net cash provided by (used in) investing activities	99,805	(224,059)
Cash flows from financing activities:
Principal payments on debt	(400,000)	(400,000)
Proceeds from exercise of stock options	1,097,016	114,656
Tax benefit from exercise of stock options	64,642	394,076
Net cash provided by financing activities	761,658	108,732
Exchange rate impact on cash	(32,228)	30,932
Increase (decrease) in cash and cash equivalents	6,898,089	(1,774,044)
Cash and cash equivalents at beginning of period	44,067,477	35,777,222
Cash and cash equivalents at end of period	$ 50,965,566	$ 34,003,178