Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 20,574,521	$ 11,757,460	$ 8,466,680
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	4,772,491	4,525,247	4,002,391
Stock-based compensation expense	1,268,070	1,151,199	1,190,697
Deferred income taxes	2,205,608	(10,269)	1,989,708
Provision for doubtful accounts	238,071	135,353	331,528
Provision for inventory	171,089	1,310,953	1,427,862
Gain on sale of assets	(126,284)
Tax benefit from exercise of stock options	(856,830)	(452,471)	(274,190)
Restructuring (credits) charges	(160,559)	1,604,256
Changes in operating assets and liabilities:
Accounts receivable	2,411,247	(4,271,129)	(2,998,037)
Inventories	(2,823,059)	(2,370,318)	224,714
Prepaid expenses and other current assets	204,519	200,453	947,263
Long-term deposits and other	101,986	33,995	179,939
Accounts payable	622,928	(2,879,330)	(6,594,292)
Accrued expenses	(376,897)	1,420,131	1,042,845
Deferred revenue	(2,795,285)	(2,858,262)	(213,888)
Income taxes payable	152,364	1,268,442	450,482
Other long-term liabilities	(418,979)	(17,033)	(568)
Net cash provided by operating activities	25,165,001	10,548,677	10,173,134
Cash flows from investing activities:
Purchase of property and equipment	(440,890)	(1,504,707)	(1,400,348)
Proceeds from sale of assets	187,735
Net cash used in investing activities	(253,155)	(1,504,707)	(1,400,348)
Cash flows from financing activities:
Principal payments on debt	(9,600,000)	(1,600,000)	(1,600,000)
Proceeds from exercise of stock options	3,053,941	388,675	160,470
Tax benefit from exercise of stock options	856,830	452,471	274,190
Net cash used in financing activities	(5,689,229)	(758,854)	(1,165,340)
Exchange rate impact on cash	43,066	5,139	(32,156)
Increase in cash and cash equivalents	19,265,683	8,290,255	7,575,290
Cash and cash equivalents at beginning of period	44,067,477	35,777,222	28,201,932
Cash and cash equivalents at end of period	63,333,160	44,067,477	35,777,222
Supplemental disclosure of cash flow information:
Cash paid for income taxes	9,841,546	6,496,000	2,651,212
Cash paid for interest	$ 125,978	$ 184,881	$ 193,880