Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 24,332,603	$ 8,962,894
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,366,411	2,270,895
Stock-based compensation expense	805,782	788,326
Deferred income taxes	(357,081)	(269,149)
Provision for inventory	147,693	229,885
Tax benefit from exercise of stock options	(6,825,828)	(7,596)
Changes in operating assets and liabilities:
Accounts receivable	(191,088)	1,796,522
Inventories	(3,030,077)	(2,324,269)
Prepaid expenses, other current and long-term assets	(10,624)	703,303
Long-term deposits and other		16,998
Accounts payable	(943,169)	878,228
Accrued expenses	(749,411)	(1,270,885)
Deferred revenue	(2,140,902)	(1,430,484)
Income taxes payable	7,014,770	(440,210)
Other long-term liabilities	(99,980)	(271,532)
Net cash provided by operating activities	20,319,099	9,632,926
Cash flows from investing activities:
Proceeds from sale of assets		246,785
Purchase of property and equipment	(677,358)	(109,871)
Net cash provided by (used in) investing activities	(677,358)	136,914
Cash flows from financing activities:
Proceeds from exercise of stock options	1,361,805	1,127,875
Tax benefit from exercise of stock options	6,825,828	7,596
Minimum tax withholding on share based awards	(6,348,900)
Principal payments on debt		(800,000)
Net cash provided by financing activities	1,838,733	335,471
Exchange rate impact on cash	65,928	(32,329)
Increase in cash and cash equivalents	21,546,402	10,072,982
Cash and cash equivalents at beginning of period	63,333,160	44,067,477
Cash and cash equivalents at end of period	$ 84,879,562	$ 54,140,459