Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income (loss) before income tax provision for income taxes [Abstract]
Domestic	$ (4,980,364)	$ 15,805,107	$ (7,706,018)
Foreign	(706,265)	(4,270,715)	(766,343)
(Loss) income before income taxes	(5,686,629)	11,534,392	(8,472,361)
Federal [Abstract]
Current	350,039	3,588,798	210,090
Deferred	0	0	0
Total federal income Taxes	350,039	3,588,798	210,090
State [Abstract]
Current	143,370	515,745	92,505
Deferred	0	0	0
Total state income taxes	143,370	515,745	92,505
Foreign [Abstract]
Current	(8,879)	1,420	0
Deferred	0	0	0
Total foreign income taxes	(8,879)	1,420	0
Total	484,530	4,105,963	302,595
State non-income taxes	200,000
Increase in uncertain tax positions	300,000
Reconciliation of federal statutory rate to effective tax rate [Abstract]
Income tax benefit at federal statutory rate (in hundredths)	(34.00%)	34.00%	(34.00%)
Increase (decrease) in tax resulting from [Abstract]
State income taxes, net of federal benefit (in hundredths)	(1.50%)	3.10%	(2.20%)
Federal research credit (in hundredths)	0.00%	(3.00%)	(1.10%)
Foreign rate differential (in hundredths)	(0.30%)	0.40%	(0.30%)
Foreign rate differential - valuation allowance (in hundredths)	4.50%	12.20%	3.40%
Change in valuation allowance (in hundredths)	28.90%	(13.30%)	32.10%
ASC 740-10 reserves (in hundredths)	5.50%	1.90%	(0.30%)
Permanent items (in hundredths)	3.50%	0.30%	5.30%
U.S. federal and state provision to return adjustment	1.90%	0.00%	0.70%
Provision for income taxes (in hundredths)	8.50%	35.60%	3.60%
Deferred Tax Assets [Abstract]
Net operating loss carry forwards	2,349,107	1,962,882
Nondeductible reserves	3,339,700	1,880,276
Nondeductible accruals	1,479,545	1,527,390
Tax credits	495,486	499,099
Deferred revenue	273,608	0
Stock-based compensation	1,865,675	2,100,606
Gross Deferred Tax Assets	9,803,121	7,970,253
Valuation allowance	(9,551,668)	(7,636,353)
Net Deferred Tax Assets	251,453	333,900
Deferred Tax Liabilities [Abstract]
Fixed Assets	(251,453)	(333,900)
Net Deferred Tax Liabilities	(251,453)	(333,900)
Net Deferred Tax Assets	0	0
Deferred tax assets related to excess tax deductions from exercise of employee stock options	18,400,000
Impact to paid-in capital resulting from exercise and expiration of employee stock options	200,000	3,200,000	200,000
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits which would affect our effective tax rate if recognized	3,300,000
Reconciliation of total gross unrecognized tax benefits [Abstract]
Balance at beginning of year	2,902,543	2,762,432	3,032,220
Tax positions related to current year [Abstract]
Increase related to positions taken in current year	69,959	173,800	146,811
Increases related to positions taken during prior year	258,112	94,069	0
Decrease related to positions take during prior year	0	0	(98,923)
Decrease related to settlements	(8,471)	0	(12,415)
Decrease resulting from statute expiration	(175,355)	(127,758)	(305,261)
Balance at end of year	3,046,788	2,902,543	2,762,432
Accrued interest and penalties related to uncertain tax positions	229,000	180,000
Open tax years	2006-2012
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	38,700,000
Tax Credit Carryforward [Line Items]
Tax credit carryforward	4,500,000
State [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	13,000,000
Tax Credit Carryforward [Line Items]
Tax credit carryforward	2,000,000
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 6,000,000