Balance Sheets (USD $)	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 6,886,191	$ 8,699,478
Accounts receivable, net	532,820	566,451
Inventories	794,665	834,526
Prepaid expenses and other current assets	406,125	462,503
Current portion of deferred costs	8,180	10,108
Total current assets	8,627,981	10,573,066
Fixed assets, net	258,805	293,897
Deferred costs and other long-term assets	4,416	10,484
Total assets	8,891,202	10,877,447
Current liabilities:
Accounts payable	225,870	257,361
Accrued compensation	559,693	647,288
Accrued expenses	1,016,875	948,843
Current portion of deferred revenue	124,693	134,185
Current portion of capital lease obligation	12,648	17,929
Total current liabilities	1,939,779	2,005,606
Deferred revenue, net of current portion	55,965	71,419
Total liabilities	1,995,744	2,077,025
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized, none outstanding	0	0
Common stock, $0.0001 par value; 50,000,000 shares authorized; 2,260,195 and 2,140,871 shares issued and outstanding at March 31, 2013 and December 31, 2012, respectively	226	214
Additional paid-in capital	147,741,590	147,393,151
Accumulated deficit	(140,846,358)	(138,592,943)
Total stockholders’ equity	6,895,458	8,800,422
Total liabilities and stockholders’ equity	$ 8,891,202	$ 10,877,447