CONDENSED BALANCE SHEETS - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 4,228,624	$ 9,647,292
Accounts receivable, net	4,648,428	4,912,356
Investments in equity securities	4,558,714
Held-to-maturity securities, at amortized cost	997,176	996,233
Inventories, net	7,414,102	7,545,094
Income taxes receivable	100,887	100,887
Other current assets	718,095	644,803
Total current assets	22,666,026	23,846,665
Property, plant, and equipment, net	10,667,900	10,851,747
Held-to-maturity securities, at amortized cost (non-current)	1,991,119	1,989,923
Income taxes receivable	100,835	100,835
Other assets	145,441	165,856
Total assets	35,571,321	36,955,026
Current liabilities:
Accounts payable	4,847,357	5,369,677
Current portion of long-term debt	302,355	406,361
Accrued compensation	597,457	540,852
Dividends payable	55,113	55,113
Accrued royalties to shareholder	665,411	769,324
Other accrued liabilities	962,210	1,467,935
Income taxes payable	10,025	10,025
Total current liabilities	7,439,928	8,619,287
Other long-term liabilities	60,794	82,359
Long-term debt, net of current maturities	2,641,199	2,639,647
Total liabilities	10,141,921	11,341,293
Commitments and contingencies - See Note 8
Preferred stock, $1 par value:
Additional paid-in capital	61,816,644	61,871,756
Accumulated deficit	(37,168,689)	(37,039,468)
Total stockholders' equity	25,429,400	25,613,733
Total liabilities and stockholders' equity	35,571,321	36,955,026
Series I, Class B
Preferred stock, $1 par value:
Preferred stock	98,500	98,500
Series II, Class B
Preferred stock, $1 par value:
Preferred stock	171,200	171,200
Series III, Class B
Preferred stock, $1 par value:
Preferred stock	129,245	129,245
Series IV, Class B
Preferred stock, $1 par value:
Preferred stock	342,500	342,500
Series V, Class B
Preferred stock, $1 par value:
Preferred stock	$ 40,000	$ 40,000

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682