Statements of Operations (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenue:
Systems Revenue	$ 15,585,538	$ 31,120,034	$ 32,661,573
Recurring Revenue	26,401,894	22,931,203	18,487,982
Total revenue	41,987,432	54,051,237	51,149,555
Cost of revenue:
Systems Cost of Goods Sold	8,576,283	12,719,200	13,240,430
Disposables Service and Accessories Cost of Goods Sold	3,921,798	2,845,487	3,781,203
Total cost of revenue	12,498,081	15,564,687	17,021,633
Gross margin	29,489,351	38,486,550	34,127,922
Operating expenses:
Research and development	12,886,488	12,244,163	14,260,854
Sales and marketing	31,635,415	30,178,818	28,694,540
General and administrative	16,908,656	15,022,689	15,010,490
Total operating expenses	61,430,559	57,445,670	57,965,884
Operating loss	(31,941,208)	(18,959,120)	(23,837,962)
Other income	3,416,383	2,060,346	911,977
Interest income	9,052	10,578	44,768
Interest expense	(3,515,402)	(3,035,291)	(4,613,240)
Net loss	$ (32,031,175)	$ (19,923,487)	$ (27,494,457)
Net loss per common share:
Basic and diluted	$ (0.58)	$ (0.39)	$ (0.63)
Weighted average shares used in computing net loss per common share:
Basic and diluted	54,826,266	50,522,001	43,344,324