CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, net of allowance	$ 30,000	$ 9,000
Notes receivable, net of allowance	$ 0	$ 125,000
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	62,266,275	60,813,673
Common stock, shares outstanding	62,266,275	60,813,673