Statements of Operations (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Sublease	$ 251,996		$ 493,061
Total revenue	6,798,111	7,551,401	13,807,985	14,523,034
Cost of revenue:
Sublease	246,531		493,061
Total cost of revenue	1,147,492	1,389,050	2,559,545	2,654,397
Gross margin	5,650,619	6,162,351	11,248,440	11,868,637
Operating expenses:
Research and development	2,695,162	2,032,394	5,654,381	3,995,020
Sales and marketing	3,236,516	3,457,416	6,546,342	7,092,413
General and administrative	1,178,469	1,298,604	2,646,629	2,537,783
Total operating expenses	7,110,147	6,788,414	14,847,352	13,625,216
Operating loss	(1,459,528)	(626,063)	(3,598,912)	(1,756,579)
Other income				2,590,361
Interest income (expense)	31,810	(6,142)	48,374	(30,757)
Net income (loss)	(1,427,718)	(632,205)	(3,550,538)	803,025
Cumulative dividend on convertible preferred stock	(357,194)	(357,518)	(710,704)	(711,107)
Net income attributable to convertible preferred stock				(42,936)
Earnings (loss) attributable to common stockholders	$ (1,784,912)	$ (989,723)	$ (4,261,242)	$ 48,982
Net income (loss) per share attributable to common stockholders:
Basic	$ (0.03)	$ (0.02)	$ (0.07)	$ (0.00)
Diluted	$ (0.03)	$ (0.02)	$ (0.07)	$ 0.00
Weighted average number of common shares and equivalents:
Basic	60,052,673	58,926,545	59,936,606	45,019,358
Diluted	60,052,673	58,926,545	59,936,606	45,728,732
Systems [Member]
Revenue:
Total revenue		$ 310,751	$ 58,051	$ 328,026
Cost of revenue:
Total cost of revenue	6,201	457,509	57,365	661,111
Disposables, Service and Accessories [Member]
Revenue:
Total revenue	6,546,115	7,240,650	13,256,873	14,195,008
Cost of revenue:
Total cost of revenue	$ 894,760	$ 931,541	$ 2,009,119	$ 1,993,286