Business and Basis of Presentation (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Organization And Basis Of Presentation [Line Items]
Accounts receivable, net	$ 477,689		$ 334,297
Net proceeds from issuance of stock and warrants	4,197	$ 453,457
Accumulated deficit	196,941,583		196,881,800
Cash and cash equivalents	5,145,167		5,226,213
Prepaid expenses and other current assets	(362,921)		(478,074)
Assets, Current	(6,965,403)		(7,089,866)
Accrued Sales Return provisions	535,000		545,000
Liabilities, Current	(2,087,993)		(2,285,390)
Operating Lease, Liability, Noncurrent	(371,827)		(461,410)
Stockholders' Equity Attributable to Parent	5,261,052	2,514,118	5,247,775	$ 2,530,234
Cost of revenues	576,289	620,190
Gross Profit	1,579,183	1,551,846
Compensation cost not yet recognized	$ 170,683
Compensation cost not yet recognized, period for recognition	1 year 2 months 12 days
Operating Lease, Right-of-Use Asset	$ (544,420)		(692,692)
Other long-term assets	(28,284)		(28,523)
Assets	(7,720,872)		(7,994,575)
Accrued Liabilities, Current	(605,489)		(998,442)
Liabilities	(2,459,820)		(2,746,800)
Allowance for doubtful accounts	25,000		$ 25,000
Other Comprehensive Income (Loss), Net of Tax	$ 0	$ 0
One Customer | Revenue | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage	36.00%
One Customer | Accounts Receivable | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage	33.00%
Three Customers [Member] | Accounts Receivable | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage			50.00%
Two Customers | Revenue | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage		36.00%