TeraWulf (WULF) S-4/A 20 Sep 21 Registration of securities issued in business combination transactions (amended) Financial data

Document And Entity Information

Document And Entity Information	6 Months Ended
	Jun. 30, 2021
Document Information [Line Items]
Document Type	S-4/A
Entity Registrant Name	IKONICS CORP
Entity Central Index Key	0001083301
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Amendment Flag	false

Condensed Balance Sheets (Curre

Condensed Balance Sheets (Current Period Unaudited) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash	$ 2,260,855	$ 3,693,845
Trade receivables, less allowance of $54,000 in 2021 and $55,000 in 2020	1,651,035	2,119,213
Inventories	1,607,828	1,644,975
Prepaid expenses and other assets	162,786	125,969
Income taxes receivable	30,412	219,451
Total current assets	5,712,916	7,803,453
PROPERTY, PLANT, AND EQUIPMENT, at cost:
Land and building	9,556,586	9,556,586
Machinery and equipment	5,271,367	5,263,586
Office equipment	1,420,494	1,417,219
Vehicles	245,674	245,674
Property, plant, and equipment, Gross	16,494,121	16,483,065
Less accumulated depreciation	(9,410,087)	(9,094,702)
Total property, plant and equipment at cost, net	7,084,034	7,388,363
INTANGIBLE ASSETS, less accumulated amortization of $205,697 in 2021 and $207,399 in 2020	245,832	243,583
Total assets	13,042,782	15,435,399
CURRENT LIABILITIES
Current portion of long-term debt	0	2,688,396
Accounts payable	1,521,736	459,836
Accrued compensation	466,547	279,755
Other accrued liabilities	99,774	168,066
Total current liabilities	2,088,057	3,596,053
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY
Preferred stock, par value $.10 per share; authorized 250,000 shares; issued none	0	0
Common stock, par value $.10 per share; authorized 4,750,000 shares; issued and outstanding 1,980,694 shares in 2021 and 1,976,354 in 2020	198,069	197,635
Additional paid-in-capital	2,902,790	2,743,930
Retained earnings	7,853,866	8,897,781
Total stockholders' equity	10,954,725	11,839,346
Total liabilities and stockholders' equity	$ 13,042,782	$ 15,435,399

Condensed Balance Sheets (Cur_2

Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 54,000	$ 55,000	$ 58,000
Intangible assets, accumulated amortization	$ 205,697	$ 207,399	$ 181,609
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10	$ 0.10
Preferred stock, authorized (in shares)	250,000	250,000	250,000
Preferred stock, issued (in shares)	0	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	4,750,000	4,750,000	4,750,000
Common stock, share issued (in shares)	1,980,694	1,976,354	1,976,354
Common stock, share outstanding (in shares)	1,980,694	1,976,354	1,976,354

Condensed Statements of Operati

Condensed Statements of Operations (Unaudited) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net sales	$ 4,251,348	$ 2,572,439	$ 7,324,756	$ 6,069,631	$ 13,432,220	$ 17,618,559
Cost of goods sold	2,822,044	2,187,544	4,899,120	4,531,504	9,527,143	12,221,370
GROSS PROFIT	1,429,304	384,895	2,425,636	1,538,127	3,905,077	5,397,189
SELLING, GENERAL AND ADMINISTRATIVE EXPENSES	1,944,502	1,202,307	3,128,093	2,983,327	5,019,604	5,483,586
RESEARCH AND DEVELOPMENT EXPENSES	128,895	201,234	263,817	384,814	671,493	870,279
LOSS FROM OPERATIONS	(644,093)	(1,018,646)	(966,274)	(1,830,014)	(1,786,020)	(956,676)
INTEREST EXPENSE	(82,498)	(24,623)	(102,340)	(46,107)	(86,561)	(90,058)
OTHER INCOME	5,138	1,766	5,175	8,683	1,223,261	61,176
LOSS BEFORE INCOME TAXES	(721,453)	(1,041,503)	(1,063,439)	(1,867,438)	(649,320)	(985,558)
INCOME TAX EXPENSE (BENEFIT)	823	0	(19,524)	(238,929)	(210,000)	(172,000)
NET LOSS	$ (722,276)	$ (1,041,503)	$ (1,043,915)	$ (1,628,509)	$ (439,320)	$ (813,558)
Earnings Per Common Share (EPS)
Basic (in dollars per share)	$ (0.37)	$ (0.53)	$ (0.53)	$ (0.82)	$ (0.22)	$ (0.41)
Diluted (in dollars per share)	$ (0.37)	$ (0.53)	$ (0.53)	$ (0.82)	$ (0.22)	$ (0.41)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING.
Basic (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253
Diluted (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253

Statements of Stockholders' Equ

Statements of Stockholders' Equity (Unaudited) - USD ($)	Common Stock	Additional Paid-in Capital	Retained Earnings	Total
BALANCE (in shares) at Dec. 31, 2018	1,983,553
BALANCE at Dec. 31, 2018	$ 198,355	$ 2,723,024	$ 10,189,651	$ 13,111,030
Net loss			(813,558)	$ (813,558)
Exercise of stock options (in shares)				0
Stock based compensation		8,821		$ 8,821
BALANCE (in shares) at Dec. 31, 2019	1,976,354			1,976,354
BALANCE at Dec. 31, 2019	$ 197,635	2,721,962	9,337,101	$ 12,256,698
Net loss	0	0	(1,628,509)	$ (1,628,509)
Exercise of stock options (in shares)				0
Stock based compensation	$ 0	7,376	0	$ 7,376
BALANCE (in shares) at Jun. 30, 2020	1,976,354
BALANCE at Jun. 30, 2020	$ 197,635	2,729,338	7,708,592	$ 10,635,565
BALANCE (in shares) at Dec. 31, 2019	1,976,354			1,976,354
BALANCE at Dec. 31, 2019	$ 197,635	2,721,962	9,337,101	$ 12,256,698
Net loss			(439,320)	$ (439,320)
Exercise of stock options (in shares)				0
Stock based compensation		21,968		$ 21,968
BALANCE (in shares) at Dec. 31, 2020	1,976,354			1,976,354
BALANCE at Dec. 31, 2020	$ 197,635	2,743,930	8,897,781	$ 11,839,346
BALANCE (in shares) at Mar. 31, 2020	1,976,354
BALANCE at Mar. 31, 2020	$ 197,635	2,725,650	8,750,095	11,673,380
Net loss	0	0	(1,041,503)	(1,041,503)
Stock based compensation	$ 0	3,688	0	3,688
BALANCE (in shares) at Jun. 30, 2020	1,976,354
BALANCE at Jun. 30, 2020	$ 197,635	2,729,338	7,708,592	$ 10,635,565
BALANCE (in shares) at Dec. 31, 2020	1,976,354			1,976,354
BALANCE at Dec. 31, 2020	$ 197,635	2,743,930	8,897,781	$ 11,839,346
Net loss	$ 0	0	(1,043,915)	$ (1,043,915)
Exercise of stock options (in shares)	3,000			3,000
Exercise of stock options	$ 300	27,390	0	$ 27,690
Restricted stock vested (in shares)	1,340
Restricted stock vested	$ 134	(134)	0	0
Stock based compensation	$ 0	131,604	0	$ 131,604
BALANCE (in shares) at Jun. 30, 2021	1,980,694			1,980,694
BALANCE at Jun. 30, 2021	$ 198,069	2,902,790	7,853,866	$ 10,954,725
BALANCE (in shares) at Mar. 31, 2021	1,977,104
BALANCE at Mar. 31, 2021	$ 197,710	2,787,733	8,576,142	11,561,585
Net loss	$ 0	0	(722,276)	(722,276)
Exercise of stock options (in shares)	2,250
Exercise of stock options	$ 225	21,074	0	21,299
Restricted stock vested (in shares)	1,340
Restricted stock vested	$ 134	(134)	0	0
Stock based compensation	$ 0	94,117	0	$ 94,117
BALANCE (in shares) at Jun. 30, 2021	1,980,694			1,980,694
BALANCE at Jun. 30, 2021	$ 198,069	$ 2,902,790	$ 7,853,866	$ 10,954,725

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (1,043,915)	$ (1,628,509)	$ (439,320)	$ (813,558)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	315,385	335,435	661,565	639,997
Amortization	98,548	18,452	36,489	43,014
Stock based compensation	131,604	7,376	21,968	8,821
Net gain on sale and disposal of equipment	0	(2,324)	(2,325)	(8,482)
Loss on intangible asset abandonment	0	16,906	16,906	92,833
Changes in working capital components:
Trade receivables	468,178	1,020,699	315,505	(219,503)
Inventories	37,147	(501,404)	535,561	(133,948)
Prepaid expenses and other assets	(36,817)	749,076	780,947	(531,554)
Income tax receivable	189,039	(247,011)	(218,082)	1,399
Accounts payable	1,061,900	(446,417)	(301,805)	114,113
Accrued expenses	118,500	(511,614)	(591,737)	512,837
Net cash provided by (used in) operating activities	1,339,569	(1,189,335)	(398,828)	(477,031)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property equipment	(11,056)	(149,916)	(149,916)	(478,353)
Proceeds from sales of equipment	0	18,297	18,297	15,596
Purchases of intangible assets	(15,958)	(12,483)	(14,910)	(19,665)
Proceeds on sale of short-term investments	0	2,205,000	2,205,000	6,125,000
Net cash (used in) provided by investing activities	(27,014)	2,060,898	2,058,471	7,578
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from paycheck protection program loan	0	1,214,500	1,214,500
Payment on long-term debt	(2,773,235)	(71,603)	(143,947)	(140,440)
Proceeds from exercise of stock options	27,690	0
Net cash (used in) provided by financing activities	(2,745,545)	1,142,897	1,070,553	(190,035)
NET (DECREASE) INCREASE IN CASH	(1,432,990)	2,014,460	2,730,196	(659,488)
CASH AT BEGINNING OF PERIOD	3,693,845	963,649	963,649	1,623,137
CASH AT END OF PERIOD	2,260,855	2,978,109	3,693,845	963,649
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest	24,089	37,998	75,227	79,008
Net cash received (paid for) income taxes, net	$ 208,562	$ (8,082)	$ 8,082	$ 9,457

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2021
Basis of Presentation
Basis of Presentation	1. Basis of Presentation The condensed balance sheet of IKONICS Corporation (the “Company”) as of June 30, 2021, and the related condensed statements of operations for the three and six months ended June 30, 2021 and 2020, the condensed statements of stockholders’ equity for the three and six months ended June 30, 2021 and 2020, and condensed cash flows for the six months ended June 30, 2021 and 2020, have been prepared without being audited. In the opinion of management, these statements reflect all adjustments (consisting of only normal recurring adjustments) necessary to present fairly the financial position of IKONICS Corporation as of June 30, 2021, and the results of operations and cash flows for all periods presented. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America, have been condensed or omitted. Therefore, these statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The results of operations for interim periods are not necessarily indicative of results that will be realized for the full fiscal year. The Company relies on cash flow generated from operations and available borrowings under its bank line of credit to fund its working capital and other operating and investing needs. The Company’s ability to borrow under the bank line of credit is based on its ability to continue to renew the maturity date of the bank line of credit. The global, regional and local spread of COVID-19 has resulted in significant global mitigation measures, including government-directed quarantines, social distancing and shelter-in-place mandates, travel restrictions and/or bans, and restricted access to certain corporate facilities and manufacturing sites. Uncertainty with respect to the severity and duration of the pandemic has contributed to periods of volatility and disruption of financial markets. While the severity and duration of the COVID-19 pandemic remain uncertain, impacts to the Company may include, but are not limited to: fluctuations in the Company’s stock price due to market volatility; a decrease in demand for the Company’s products; reduced profitability; supply chain disruptions impeding the Company’s ability to ship and/or receive product; potential interruptions or limitations to manufacturing operations imposed by local, state or federal governments; shortages of key raw materials; workforce absenteeism and distraction; labor shortages; customer credit concerns; cyber security and data accessibility disruptions due to remote working arrangements; reduced sources of liquidity; increased borrowing costs; and potential asset impairment charges. Business disruptions and market volatility resulting from the COVID-19 pandemic could continue to have a material adverse impact on the Company’s results of operations, financial condition and cash flows. Based on the Company’s current cash position, and expected future cash flows, the Company believes it will have sufficient cash to fund its operations beyond twelve months from the date of the issuance of the accompanying unaudited condensed financial statements. Definitive Transaction Agreement with TeraWulf, Inc. On June 25, 2021, the Company announced that its board of directors, along with the board of directors of TeraWulf Inc. (“TeraWulf”), unanimously approved a definitive agreement (as amended, the "Agreement”) under which the Company will combine with TeraWulf under a new holding company in a strategic business combination (the “Transaction”). Upon consummation of the Transaction, each outstanding share of the Company’s common stock will receive $5.00 in cash, one contingent value right (“CVR”), and one share of the combined company's common stock. Through the CVRs, which will not be publicly traded, the Company’s shareholders will be entitled to receive 95% of the net proceeds from any sale of the IKONICS legacy business completed during the 18 months following the closing of the business combination, and will expire at the end of such 18 month period with respect to any portion of the IKONICS legacy business which has not been sold. The shares of the combined company's common stock to be received by the Company’s shareholders will collectively represent 2% of the combined company's pro forma common equity ownership. Following consummation of the Transaction, the legacy business of IKONICS will be operated consistent with past practices but will be positioned for sale on terms that are acceptable to the board of directors of the combined company. The Transaction is expected to close in the second half of 2021, subject to the receipt of regulatory approvals, the approval of IKONICS and TeraWulf shareholders, and other customary closing conditions. The Agreement contains certain termination rights for both IKONICS and TeraWulf, including if the Transaction is not completed on or before December 31, 2021. The Agreement provides that the Company will be obligated to pay TeraWulf a termination fee of $1.2 million, and TeraWulf will be obligated to pay the Company a termination fee of $10.0 million, if the Agreement is terminated under certain circumstances. The Agreement does not contain any post-Closing indemnification obligations with respect to the Parties. In the second quarter of 2021, in connection with the Transaction, the Company incurred pre-tax expenses of approximately $703,000 related to professional fees which are recorded in selling, general and administrative expenses in the condensed consolidated statement of operations. Legal Proceedings From time to time, the Company is involved in legal proceedings and regulatory proceedings arising from the Company’s operations. The Company establishes reserves for specific liabilities in connection with legal actions that are deemed to be probable and estimable. Except as set forth below, the Company is not currently a party to any proceeding, the adverse outcome of which would have a material adverse effect on its financial position or results of operations. On August 3, 2021, one complaint was filed by a purported shareholder of the Company in the United States District Court for the Southern District of New York, captioned Stein v. Ikonics Corporation, et al. , No. 1:21-cv-6550. On August 11, 2021, another complaint was filed by a purported shareholder of the Company in the United States District Court for the Eastern District of New York, captioned Bendimez v. Ikonics Corporation, et al. , No. 1:21-cv-04514. The complaints name as defendants, the Company and the members of its board of directors and allege violations of Sections 14(a) and 20(a) of the Securities Exchange Act of 1934 and certain SEC rules and regulations promulgated thereunder. Each complaint generally alleges, among other things, that certain disclosure in a version of the preliminary proxy statement/prospectus contained in the registration statement on Form S-4 originally filed with the SEC on July 30, 2021 misrepresented and/or omitted material information. The complaints seek, among other remedies, injunctive relief, including enjoining defendants from proceeding with or consummating the mergers, rescissory damages, and an award of costs and expenses, including attorneys’ and experts' fees and expenses. The Company and the members of its board of directors have not yet responded to either complaint but believe they are without merit. However, there can be no assurance that the Company will prevail in any lawsuit. Additionally, similar lawsuits may be filed between the date of this filing and the date of the special meeting.

Inventories

Inventories	6 Months Ended
	Jun. 30, 2021
Inventory Disclosure [Abstract]
Inventories	2. Inventories The major components of inventories as of June 30, 2021 and December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Jun 30, 2021 Dec 31, 2020 Raw materials ​ $ 1,286,151 ​ $ 1,323,655 Work-in-progress ​ 399,738 ​ 428,753 Finished goods ​ 1,140,543 ​ 1,065,458 Reduction to LIFO cost ​ (1,218,604) ​ (1,172,891) Total Inventories ​ $ 1,607,828 ​ $ 1,644,975 ​

Earnings Per Common Share (EPS)

Earnings Per Common Share (EPS)	6 Months Ended
	Jun. 30, 2021
Earnings Per Common Share (EPS)
Earnings Per Common Share (EPS)	3. Earnings Per Common Share (EPS) Basic EPS is calculated using net loss divided by the weighted average of common shares outstanding. Diluted EPS is calculated similarly to Basic EPS except that the weighted average number of common shares outstanding is increased to include the number of additional common shares that would have been outstanding if the potential dilutive common shares, such as those shares subject to options, had been issued. The options and restricted stock units disclosed in Note 4 have been excluded from the computation because of their antidilutive effect. Shares used in the calculation of diluted EPS are summarized below: ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Jun 30, 2021 Jun 30, 2020 Weighted average common shares outstanding ​ 1,977,959 1,976,354 Dilutive effect of stock options and restricted stock units ​ — — Weighted average common and common equivalent shares outstanding ​ 1,977,959 1,976,354 ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ Jun 30, 2021 Jun 30, 2020 Weighted average common shares outstanding 1,977,368 1,976,354 Dilutive effect of stock options and restricted stock units — — Weighted average common and common equivalent shares outstanding 1,977,368 1,976,354 ​ If the Company was in a net income position for the three and six months ended June 30, 2021, 13,500 options with a weighted average exercise price of $6.18 would have been included as part of the computation of common share equivalents as the options would have been dilutive, while 10,000 options with a weighted average exercise price of $11.50 would have remained excluded because these options were anti-dilutive. If the Company was in a net income position for the three and six months ended June 30, 2021, 87,110 restricted stock units would have been included as part of the computation of common share equivalents as the restricted stock units would have been dilutive. If the Company was in a net income position for the three and six months ended June 30, 2020, all 21,500 options outstanding with a weighted average exercise price of $7.38 would have remained excluded from the computation of common share equivalents as the options were anti-dilutive.

Stock-based Compensation

Stock-based Compensation	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Stock-Based Compensation
Stock-Based Compensation	4. Stock-Based Compensation The Company maintains the 2019 Equity Incentive Plan (the “2019 Plan”). The 2019 Plan replaced the 1995 Incentive Stock Option Plan (the “1995 Plan) upon its ratification by shareholders in April 2019. The 1995 plan authorized the issuance of up to 442,750 shares of common stock through grants of restricted stock units and options. Of those shares, 1,000 were subject to outstanding options as of June 30, 2021. Awards granted under the 1995 Plan will remain in effect until they are exercised or expire according to their terms. At the time the 2019 Plan was approved, there were 102,157 shares reserved for future grants under the 1995 Plan which will no longer be available for future grants. Under the terms of the 2019 Plan, the number of shares of common stock that may be the subject of awards and issued under the 2019 Plan was initially set at 102,157. Subsequent to the approval of the 2019 Plan, 12,750 outstanding options granted under the 1995 Plan were forfeited. Under the terms of the 2019 Plan, those forfeited options are added back to the 2019 Plan reserve pool. As of June 30, 2021, 90,850 restricted stock units (RSUs) and 23,250 options have been granted under the 2019 Plan, of which 750 stock options and 2,400 RSUs have been forfeited, bringing the number of shares of common stock available for future awards under the 2019 Plan to 3,957. The Company charged compensation cost of approximately $131,600 against the loss for the six months ended June 30, 2021 and approximately $7,400 for the six months ended June 30, 2020. As of June 30, 2021, there was approximately $674,000 of unrecognized compensation cost related to unvested share-based compensation awards. That cost is expected to be recognized over the next four years . The Company receives a tax deduction for certain stock option exercises during the period in which the options are exercised, generally for the excess of the market price at the time the stock options are exercised over the exercise price of the options, which increases additional paid in capital and reduces income taxes payable. Proceeds from the exercise of 3,000 stock options with an intrinsic value of approximately $24,000 were approximately $27,700 for the six months ended June 30, 2021. No stock options were exercised during the six months ended June 30, 2020. There were 10,000 options granted during the six months ended June 30, 2021 and 2020. The fair value of options granted during the six months ended June 30, 2021 and 2020 were estimated using the Black Scholes option pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 Dividend yield ​ — ​ — ​ Expected volatility ​ 51.6 % ​ 40.3 % Expected life of option (years) ​ 10 ​ 10 ​ Risk-free interest rate ​ 0.5 % ​ 1.4 % Fair value of each option on grant date ​ $ 6.84 ​ $ 2.90 ​ ​ Stock option activity during the six months ended June 30, 2021 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2021 17,500 ​ $ 6.97 Granted 10,000 ​ 11.50 Exercised (3,000) ​ 9.23 Expired and forfeited (1,000) ​ 10.75 Outstanding at June 30, 2021 23,500 ​ $ 8.45 Exercisable at June 30, 2021 5,165 ​ $ 6.54 ​ The aggregate intrinsic value of all options outstanding and for those exercisable at June 30, 2021 was approximately $58,700 and $20,700, respectively. There were 36,550 RSUs granted during the six months ended June 30, 2021. The shares underlying the awards were assigned a weighted average value of $11.01 per share, based on the closing price of the Company’s common stock on the date of grants. These awards scheduled vesting period ranges from some awards vesting at the time of the grant up to four years . No RSUs were granted during the six months ended June 30, 2020. RSU activity during the six months ended June 30, 2021 is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested shares at January 1, 2021 54,300 ​ $ 6.11 Granted 36,550 ​ 11.01 Vested (1,340) ​ 11.30 Forfeited or surrendered (2,400) ​ 6.11 Unvested shares at June 30, 2021 87,110 ​ 8.09 ​	6. STOCKHOLDERS’ EQUITY The Company maintains the 2019 Equity Incentive Plan (the “2019 Plan”). The 2019 Plan replaced the 1995 Incentive Stock Option Plan (the “1995 Plan) upon its ratification by shareholders in April 2019. The 1995 plan authorized the issuance of up to 442,750 shares of common stock through grants of restricted stock units and options. Of those shares, 5,000 were subject to outstanding options as of December 31, 2020. Awards granted under the 1995 Plan will remain in effect until they are exercised or expire according to their terms. At the time the 2019 Plan was approved, there were 102,157 shares reserved for future grants under the 1995 Plan which will no longer be available for future grants. Under the terms of the 2019 Plan, the number of shares of common stock that may be the subject of awards and issued under the 2019 Plan was initially set at 102,157. Subsequent to the approval of the 2019 Plan, 11,750 outstanding options granted under the 1995 Plan were forfeited. Under the terms of the 2019 Plan, those forfeited options are added back to the 2019 Plan reserve pool. As of December 31, 2020, 54,300 restricted stock units (RSUs) and 13,250 options have been granted under the 2019 Plan, of which 750 stock options have been forfeited, bringing the number of shares of common stock available for future awards under the 2019 Plan to 47,107. The Company charged compensation expense of $22,000 and $9,000 against the loss in 2020 and 2019, respectively. As of December 31, 2020, there was approximately $348,000 of unrecognized compensation expense related to unvested share-based compensation awards granted which is expected to be recognized over the next three No stock options were exercised in 2020 or 2019 The fair value of options granted was estimated using the Black-Scholes option pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Dividend yield ​ 0 ​ 0 ​ Expected volatility ​ 40.3 % ​ 37.5 % Expected life of option (years) ​ 10 ​ 5 ​ Risk-free interest rate ​ 1.4 % ​ 1.7 % Fair value of each option on grant date ​ $ 2.90 ​ $ 2.53 ​ ​ There were 10,000 and 3,250 options granted during 2020 and 2019, respectively. A summary of the status of the Company’s stock option plan as of December 31, 2020 and changes during the year then ended is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2020 19,250 ​ $ 11.32 Granted 10,000 ​ 5.67 Exercised — ​ — Expired and forfeited (11,750) ​ 12.99 Outstanding at December 31, 2020 17,500 ​ $ 6.97 Exercisable at December 31, 2020 5,332 ​ $ 9.19 ​ There were 54,300 RSUs granted in 2020. The shares underlying the awards were assigned a weighted average value of $6.11 per share, which was the closing price of the Company’s common stock on the date of grants. These awards are scheduled to vest over three RSU activity during the year ended December 31, 2020 is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Shares Fair Value Unvested shares at January 1, 2020 — ​ — Granted 54,300 ​ $ 6.11 Vested — ​ — Forfeited or surrendered — ​ — Unvested shares at December 31, 2020 54,300 ​ 6.11 ​ In 2017, the Company’s board of directors had authorized the repurchase of 100,000 shares of common stock. A total of

Segment Information

Segment Information	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Segment Information
Segment Information	5. Segment Information The Company’s reportable segments are strategic business units that offer different products and have varied customer bases. There are four reportable segments: Chromaline, IKONICS Imaging, Digital Texturing (DTX) and Advanced Material Solutions (AMS). Chromaline sells screen printing film, emulsions, and inkjet receptive film primarily to distributors and some end users. IKONICS Imaging sells photo resistant film, art supplies, glass, and related abrasive etching equipment to both end users and distributors. AMS provides sound deadening and weight reduction technology to the aerospace industry along with products and services for etched composites, ceramics, glass and silicon wafers. DTX includes products and customers related to patented and proprietary inkjet technology used for mold texturing and prototyping. The accounting policies applied to determine the segment information are the same as those described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. Management evaluates the performance of each segment based on the components of divisional income (loss). Assets and liabilities are not allocated to segments, except for trade receivables. Financial information with respect to the reportable segments follows: For the three months ended June 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 2,653,733 ​ $ 1,264,855 ​ $ 85,444 ​ $ 247,316 ​ $ — ​ $ 4,251,348 Cost of goods sold ​ 1,905,738 ​ 644,071 ​ 34,260 ​ 237,975 ​ — ​ 2,822,044 Gross profit ​ 747,995 ​ 620,784 ​ 51,184 ​ 9,341 ​ — ​ 1,429,304 Selling general and administrative* ​ 289,928 ​ 259,219 ​ 32,001 ​ 58,869 ​ 1,304,485 ​ 1,944,502 Research and development* ​ — ​ — ​ — ​ — ​ 128,895 ​ 128,895 Income (loss) from operations ​ $ 458,067 ​ $ 361,565 ​ $ 19,183 ​ $ (49,528) ​ $ (1,433,380) ​ $ (644,093) ​ For the three months ended June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 1,619,986 ​ $ 625,800 ​ $ 49,053 ​ $ 277,600 ​ $ — ​ $ 2,572,439 Cost of goods sold ​ 1,407,362 ​ 419,985 ​ 24,346 ​ 335,851 ​ — ​ 2,187,544 Gross profit (loss) ​ 212,624 ​ 205,815 ​ 24,707 ​ (58,251) ​ — ​ 384,895 Selling general and administrative * ​ 366,136 ​ 224,573 ​ 30,059 ​ 57,035 ​ 524,504 ​ 1,202,307 Research and development* ​ — ​ — ​ — ​ — ​ 201,234 ​ 201,234 Loss from operations ​ $ (153,512) ​ $ (18,758) ​ $ (5,352) ​ $ (115,286) ​ $ (725,738) ​ $ (1,018,646) ​ For the six months ended June 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 4,352,414 ​ $ 2,351,456 ​ $ 161,755 ​ $ 459,131 ​ $ — ​ $ 7,324,756 Cost of goods sold ​ 3,140,523 ​ 1,193,726 ​ 77,052 ​ 487,819 ​ — ​ 4,899,120 Gross profit (loss) ​ 1,211,891 ​ 1,157,730 ​ 84,703 ​ (28,688) ​ — ​ 2,425,636 Selling general and administrative* ​ 547,930 ​ 475,755 ​ 62,040 ​ 117,490 ​ 1,924,878 ​ 3,128,093 Research and development* ​ — ​ — ​ — ​ — ​ 263,817 ​ 263,817 Income (loss) from operations ​ $ 663,961 ​ $ 681,975 ​ $ 22,663 ​ $ (146,178) ​ $ (2,188,695) ​ $ (966,274) ​ For the six months ended June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 3,584,326 ​ $ 1,595,899 ​ $ 161,582 ​ $ 727,824 ​ $ — ​ $ 6,069,631 Cost of goods sold ​ 2,825,631 ​ 897,708 ​ 76,092 ​ 732,073 ​ — ​ 4,531,504 Gross profit (loss) ​ 758,695 ​ 698,191 ​ 85,490 ​ (4,249) ​ — ​ 1,538,127 Selling general and administrative* ​ 792,355 ​ 503,435 ​ 64,432 ​ 160,144 ​ 1,462,961 ​ 2,983,327 Research and development* ​ — ​ — ​ — ​ — ​ 384,814 ​ 384,814 Income (loss) from operations ​ $ (33,660) ​ $ 194,756 ​ $ 21,058 ​ $ (164,393) ​ $ (1,847,775) ​ $ (1,830,014) * The Company does not allocate all selling, general and administrative expenses or any research and development expenses to its operating segments for internal reporting. Trade receivables by segment as of June 30, 2021 and December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Jun 30, 2021 Dec 31, 2020 Chromaline ​ $ 1,150,630 ​ $ 1,676,592 IKONICS Imaging ​ 356,216 ​ 396,116 DTX ​ 26,759 ​ 35,983 AMS ​ 155,409 ​ 57,676 Unallocated ​ (37,979) ​ (47,154) Total ​ $ 1,651,035 ​ $ 2,119,213 ​	5. SEGMENT INFORMATION The Company’s reportable segments are strategic business units that offer different products and have varied customer bases. There are four reportable segments: Chromaline, IKONICS Imaging, Digital Texturing (DTX) and Advanced Material Solutions (AMS). Chromaline sells screen printing film, emulsions, and inkjet receptive film primarily to distributors and some end users. IKONICS Imaging sells photo resistant film, art supplies, glass, and related abrasive etching equipment to both end users and distributors. AMS provides sound deadening and weight reduction technology to the aerospace industry along with products and services for etched composites, ceramics, glass and silicon wafers. DTX includes products and customers related to patented and proprietary inkjet technology used for mold texturing and prototyping.The accounting policies of the segments are the same as those described in the summary of significant accounting policies included in Note 1. Management evaluates the performance of each segment based on the components of divisional income, and does not allocate assets and liabilities to segments except for trade receivables. Financial information with respect to the reportable segments follows: For the year ended December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline ​ Imaging ​ DTX ​ AMS ​ Unalloc. ​ Total Net sales ​ $ 8,475,743 ​ $ 3,709,318 ​ $ 294,929 ​ $ 952,230 $ — ​ $ 13,432,220 Cost of goods sold ​ 6,222,902 ​ 1,972,076 ​ 140,866 ​ 1,191,299 ​ — ​ 9,527,143 Gross profit (loss) ​ 2,252,841 ​ 1,737,242 ​ 154,063 ​ (239,069) ​ — ​ 3,905,077 Selling, general, and administrative* ​ 1,297,045 ​ 880,404 ​ 125,752 ​ 275,147 ​ 2,441,256 ​ 5,019,604 Research and development* ​ — ​ — ​ — ​ — ​ 671,493 ​ 671,493 Income (loss) from operations ​ $ 955,796 ​ $ 856,838 ​ $ 28,311 ​ $ (514,216) ​ $ (3,112,749) ​ $ (1,786,020) ​ For the year ended December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 11,472,111 ​ $ 4,191,175 ​ $ 393,804 ​ $ 1,561,469 ​ $ — ​ $ 17,618,559 Cost of goods sold ​ 8,389,404 ​ 2,273,641 ​ 157,650 ​ 1,400,675 ​ — ​ 12,221,370 Gross profit ​ 3,082,707 ​ 1,917,534 ​ 236,154 ​ 160,794 ​ — ​ 5,397,189 Selling, general, and administrative* ​ 1,832,473 ​ 1,081,847 ​ 149,924 ​ 361,342 ​ 2,058,000 ​ 5,483,586 Research and development* ​ — ​ — ​ — ​ — ​ 870,279 ​ 870,279 Income (loss) from operations ​ $ 1,250,234 ​ $ 835,687 ​ $ 86,230 ​ $ (200,548) ​ $ (2,928,279) ​ $ (956,676) * The Company does not allocate all general and administrative expenses or any research and development expenses to its operating segments for internal reporting. Trade receivables by segment as of December ​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Chromaline ​ $ 1,676,592 ​ $ 1,916,066 IKONICS Imaging ​ 396,116 ​ 304,791 DTX ​ 35,983 ​ 13,919 AMS ​ 57,676 ​ 252,363 Unallocated ​ (47,154) ​ (52,421) ​ ​ ​ ​ ​ ​ ​ Total ​ $ 2,119,213 ​ $ 2,434,718 ​

Income Taxes

Income Taxes	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Income Taxes
Income Taxes	6. Income Taxes The Company records its interim provision for income taxes by applying its estimated annual effective tax rate to the year-to-date pre-tax income and adjusting for discrete tax items recorded in the period. Deferred income taxes result from temporary differences between the reporting of amounts for financial statement purposes and income tax purposes. These differences relate primarily to different methods used for income tax reporting purposes, including for depreciation and amortization, warranty and vacation accruals, and deductions related to allowances for doubtful accounts receivable and inventory reserves. The provision for income taxes included current federal and state income tax expense, as well as deferred federal and state income tax expense. Management assesses the available positive and negative evidence to estimate whether sufficient future taxable income will be generated to permit use of the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss incurred over the three-year period ended June 30, 2021. Such objective evidence limits the ability to consider other subjective evidence, such as our projections for future growth. On the basis of this evaluation, as of June 30, 2021, a full valuation allowance has been recorded to reserve for deferred tax assets entirely, which are not expected to be realized. The valuation allowance will be reevaluated on a quarterly basis and may change if estimates of future taxable income during the carryforward period is increased or if objective negative evidence in the form of cumulative losses is no longer present and additional weight is given to subjective evidence such as our projections for growth The effective tax rate for the three months ended June 30, 2021 was a benefit of 0.1%, compared to an effective tax rate 0.0% for the three months ended June 30, 2020. The Company recorded an income tax benefit of $1,000 and a benefit of $0 for the three months ended June 30, 2021 and 2020, respectively. The effective tax rate for the six months ended June 30, 2021 was a benefit of 1.8%, compared to a benefit 12.8% for the six months ended June 30, 2020. The primary driver of the change in the Company’s effective tax rate is attributable to additional benefit from an net operating loss carryback claim recorded in the prior year. The Company recorded an income tax benefit of $19,000 and a benefit of $239,000 for the six months ended June 30, 2021 and 2020, respectively. The Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority is more-likely -than-not to sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the condensed consolidated financial statements is the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant tax authority. As of June 30, 2021, the Company has no unrecognized tax benefits. This Company is not currently under examination in any jurisdiction. In the event of any future tax assessments, the Company has elected to record the income taxes and any related interest and penalties as income tax expense on the statement of operations.	2. INCOME TAXES Income tax benefit for the years ended December 31, 2020 and 2019 consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Current: ​ ​ ​ ​ ​ ​ Federal ​ $ (216,000) ​ $ — State ​ ​ 6,000 ​ ​ 11,000 ​ ​ ​ (210,000) ​ ​ 11,000 Deferred — Federal ​ ​ — ​ ​ (183,000) ​ ​ $ (210,000) ​ $ (172,000) ​ The expected (benefit) provision for income taxes, computed by applying the U.S. federal income tax rate of 21% to income (loss) before taxes, is reconciled to income benefit as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 Expected provision for federal income taxes ​ $ (136,000) ​ $ (207,000) State income taxes, net of federal benefit ​ (24,000) ​ (7,000) Permanent items ​ (249,000) ​ 11,000 Research and development credit ​ (23,000) ​ (29,000) Change in valuation allowance ​ 440,000 ​ 51,000 Change in tax law allowing NOL carryback claim ​ (217,000) ​ — Prior year true-ups and other ​ (1,000) ​ 9,000 ​ ​ $ (210,000) ​ $ (172,000) ​ Net deferred tax liabilities consist of the following as of December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Deferred tax liabilities: ​ ​ ​ ​ ​ ​ Accrued vacation ​ $ 33,000 ​ $ 21,000 Inventories reserve ​ 17,000 ​ 42,000 Allowance for doubtful accounts ​ 2,000 ​ 3,000 Allowance for sales returns ​ 10,000 ​ 10,000 Research and development credit carryforward ​ 285,000 ​ 245,000 Accrued self-insured medical ​ — ​ 3,000 Property and equipment ​ (257,000) ​ (295,000) Patents ​ (50,000) ​ (53,000) Net operating loss ​ 411,000 ​ 230,000 Other ​ 17,000 ​ 8,000 Valuation allowance ​ (468,000) ​ (214,000) Net deferred tax liabilities ​ $ — ​ $ — ​ As of December 31, 2020, the Company has federal net operating loss carry-forwards and research and development credit carryovers of $1,847,000 and $104,000, respectively, and begin expiring in 2037. The Company’s state net operating loss carryforwards and research and development credit carryovers at December 31, 2020 total $468,000 and $214,000, respectively, and begin expiring in 2026. The Company is subject to federal and state taxation. As of December 31, 2020, with few exceptions, the Company is no longer subject to examination prior to tax year 2017. In accounting for uncertainty in income taxes, we recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more likely than not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority. As of December 31, 2020, the Company does not have any unrecognized tax benefits. The Company recognizes interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. We do not expect any material changes in our unrecognized tax benefits over the next 12 months. The Company establishes a valuation allowance to reduce the deferred tax assets when it is more likely than not that a deferred tax asset will not be realizable. On the basis of this evaluation, as of December 31, 2020 and 2019, a full valuation allowance has been recorded to reserve for deferred tax assets, which are not expected to be realized.

Long-term Debt

Long-term Debt	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Long-Term Debt
Long-Term Debt	7. Long-Term Debt Duluth Economic Development Authority Loan On April 1, 2016, the Company entered into a financing agreement (the “Financing Agreement”) under which the Duluth Economic Development Authority (the “Issuer”) agreed to sell $3,415,000 of its Tax Exempt Industrial Revenue Bonds, Series 2016 (IKONICS Project) (the “Bonds”) to Wells Fargo Bank, National Association (the “Bank”), and the Bank agreed to lend to the Company the proceeds received from the sale of the Bonds (the “Loan”). The closing of the sale of the Bonds occurred on April 29, 2016. The proceeds from the Loan were used to finance the construction of a 27,300-square foot building as well as related equipment for use in the Company’s manufacture of sound deadening technology used in the aerospace industry and products consisting of etched composites, ceramics, glass and silicon wafers, to be located in Duluth, Minnesota (the “Project”). The Loan required monthly payments of approximately $18,000, including interest. The Loans interest rate was 2.60% per year, subject to change based upon changes to the maximum federal corporate tax rate. Including debt costs of approximately $139,000, the Loan’s effective interest rate was 3.23%. During the first six months of 2021, the Company was informed that the bank will require the Company to repay the outstanding principal and any outstanding accrued and unpaid interest on April 1, 2021. On April 1, 2021, the Company repaid the entire loan including principal amount of $2.7 million and interest of $6,100 with existing cash on hand. When the loan was repaid, $82,000 of unamortized deferred financing costs were written off and charged to interest expense. Line of Credit The Company also has a bank line of credit providing for borrowings of up to $2,050,000 which expires on August 30, 2021 and bears interest at 1.8 percentage points over the 30-day LIBOR rate. The Company did not utilize this line of credit during the first six months of 2021 or 2020 and there were no borrowings outstanding as of June 30, 2021 or December 31, 2020. There are no financial covenants related to the line of credit, and the line of credit is collateralized by the Company’s assets.	7. LONG-TERM DEBT Duluth Economic Development Authority Loan On April 1, 2016, the Company entered into a financing agreement (the “Financing Agreement”) under which the Duluth Economic Development Authority (the “Issuer”) agreed to sell , including interest. The Loan bears interest at a rate of The Company is subject to certain customary covenants set forth in the associated covenant agreement, including a requirement that the Company maintain a debt service coverage ratio of not less than 1.25 to 1.00. The Loan is subject to mandatory purchase provisions, under which any owners of the Bonds (the “Owners”) may tender the Bonds to the Issuer on April 1, 2021, which would result in the Company repaying the outstanding loan principal and any outstanding accrued and unpaid interest to the Issuer at that time. If in the event the Bonds are not repurchased on April 1, 2021, the Bonds shall be subject to the interest rate and redemption provisions set forth in the associated covenant agreement. Subsequent to December 31, 2020 the Company was informed that the bank will recall the loan and require the Company to repay the outstanding principal and any outstanding accrued and unpaid interest on April 1, 2021. As of December 31, 2020, the Company reclassified the entire Loan from long-term debt to current liability. The remaining principal payments required under the agreement for years ended December 31, and the current and long-term portion of the principal, are as follows: ​ ​ ​ ​ ​ 2021 ​ 2,773,000 Less: Unamortized debt issuance costs ​ 85,000 Less: Current portion ​ 2,688,000 Long-term portion ​ $ — ​ In connection with the agreement, the Company incurred debt issuance costs of approximately $139,000 during 2016, which were deferred and are being amortized over the term of the Financing Agreement. Amortization of debt issuance costs was approximately $11,000 for 2020 and 2019 and is included in interest expense. Debt issuance costs of $85,000 are netted against long-term debt and current portion of long-term debt, respectively as of December 31, 2020 and 2019. The entire $85,000 of unamortized debt costs will be expensed when the loan is repaid in 2021. Paycheck Protection Program Loan On April 18, 2020, Company entered into a loan pursuant to the Paycheck Protection Program under the CARES Act, as administered by the U.S. Small Business Administration (the “SBA”). The loan, in the principal amount of $1,214,500 (the “PPP Loan”), was disbursed by BMO Harris Bank National Association (“Lender”) on April 22, 2020, pursuant to a Paycheck Protection Program Promissory Note and Agreement (the “Note and Agreement”). Under the CARES Act, loan forgiveness is available for the sum of documented payroll costs, covered rent payments, and covered utilities during an eight or twenty four-week period beginning on the approval date of the PPP Loan. For purposes of the CARES Act, payroll costs exclude compensation of an individual employee earning more than $100,000, prorated annually. Not more than 40% of the forgiven amount may be for non-payroll costs. Forgiveness is reduced if full-time headcount declines, or if salaries and wages for employees with salaries of $100,000 or less annually are reduced by more than 25%. During the fourth quarter of 2020, the Company submitted an application for 100% forgiveness of the PPP Loan. Prior to end of 2020, both the lender and the SBA forgave 100% of the Company’s PPP loan. The Company accounts for the PPP Loan as debt in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 470, Debt and accrues interest in accordance with the interest method under FASB ASC 835-30. When the loan was forgiven, the Company reduced the liability by the amount forgiven and recorded a gain on extinguishment in the statement of operations. Line of Credit The Company also has a bank line of credit providing for borrowings of up to $2,050,000 which expires on August 30, 2021 and bears interest at 1.8 percentage points over the 30-day LIBOR rate. The Company did not utilize this line of credit during 2020 or 2019 and there were no borrowings outstanding as of December 31, 2020 or 2019.There are no financial covenants related to the line of credit, and the Company expects that it will secure a similar line of credit when the current line of credit expires. Both the Duluth Development Authority Loan and the line of credit are collateralized by substantially all assets of the Company.

Inventories (Tables)

Inventories (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Major components of inventories	​ ​ ​ ​ ​ ​ ​ ​ ​ Jun 30, 2021 Dec 31, 2020 Raw materials ​ $ 1,286,151 ​ $ 1,323,655 Work-in-progress ​ 399,738 ​ 428,753 Finished goods ​ 1,140,543 ​ 1,065,458 Reduction to LIFO cost ​ (1,218,604) ​ (1,172,891) Total Inventories ​ $ 1,607,828 ​ $ 1,644,975	​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Raw materials ​ $ 1,323,655 ​ $ 1,667,154 Work-in-progress ​ 428,753 ​ 419,906 Finished goods ​ 1,065,458 ​ 1,449,854 Reduction to LIFO cost ​ (1,172,891) ​ (1,356,378) ​ ​ ​ ​ ​ ​ ​ Total Inventories ​ $ 1,644,975 ​ $ 2,180,536

Earnings Per Common Share (EP_2

Earnings Per Common Share (EPS) (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Earnings Per Common Share (EPS)
Shares used in the calculation of diluted EPS	​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Jun 30, 2021 Jun 30, 2020 Weighted average common shares outstanding ​ 1,977,959 1,976,354 Dilutive effect of stock options and restricted stock units ​ — — Weighted average common and common equivalent shares outstanding ​ 1,977,959 1,976,354 ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ Jun 30, 2021 Jun 30, 2020 Weighted average common shares outstanding 1,977,368 1,976,354 Dilutive effect of stock options and restricted stock units — — Weighted average common and common equivalent shares outstanding 1,977,368 1,976,354	​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Weighted average common shares outstanding ​ 1,976,354 ​ 1,980,253 Dilutive effect of stock options and restricted stock units — ​ — Weighted average common and common equivalent shares outstanding 1,976,354 ​ 1,980,253

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Stock-Based Compensation
Fair value of options granted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 Dividend yield ​ — ​ — ​ Expected volatility ​ 51.6 % ​ 40.3 % Expected life of option (years) ​ 10 ​ 10 ​ Risk-free interest rate ​ 0.5 % ​ 1.4 % Fair value of each option on grant date ​ $ 6.84 ​ $ 2.90 ​	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Dividend yield ​ 0 ​ 0 ​ Expected volatility ​ 40.3 % ​ 37.5 % Expected life of option (years) ​ 10 ​ 5 ​ Risk-free interest rate ​ 1.4 % ​ 1.7 % Fair value of each option on grant date ​ $ 2.90 ​ $ 2.53 ​
Stock option activity	Stock option activity during the six months ended June 30, 2021 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2021 17,500 ​ $ 6.97 Granted 10,000 ​ 11.50 Exercised (3,000) ​ 9.23 Expired and forfeited (1,000) ​ 10.75 Outstanding at June 30, 2021 23,500 ​ $ 8.45 Exercisable at June 30, 2021 5,165 ​ $ 6.54	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2020 19,250 ​ $ 11.32 Granted 10,000 ​ 5.67 Exercised — ​ — Expired and forfeited (11,750) ​ 12.99 Outstanding at December 31, 2020 17,500 ​ $ 6.97 Exercisable at December 31, 2020 5,332 ​ $ 9.19
RSU activity	RSU activity during the six months ended June 30, 2021 is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested shares at January 1, 2021 54,300 ​ $ 6.11 Granted 36,550 ​ 11.01 Vested (1,340) ​ 11.30 Forfeited or surrendered (2,400) ​ 6.11 Unvested shares at June 30, 2021 87,110 ​ 8.09	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Shares Fair Value Unvested shares at January 1, 2020 — ​ — Granted 54,300 ​ $ 6.11 Vested — ​ — Forfeited or surrendered — ​ — Unvested shares at December 31, 2020 54,300 ​ 6.11

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Information
Reportable segments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline ​ Imaging ​ DTX ​ AMS ​ Unalloc. ​ Total Net sales ​ $ 8,475,743 ​ $ 3,709,318 ​ $ 294,929 ​ $ 952,230 $ — ​ $ 13,432,220 Cost of goods sold ​ 6,222,902 ​ 1,972,076 ​ 140,866 ​ 1,191,299 ​ — ​ 9,527,143 Gross profit (loss) ​ 2,252,841 ​ 1,737,242 ​ 154,063 ​ (239,069) ​ — ​ 3,905,077 Selling, general, and administrative* ​ 1,297,045 ​ 880,404 ​ 125,752 ​ 275,147 ​ 2,441,256 ​ 5,019,604 Research and development* ​ — ​ — ​ — ​ — ​ 671,493 ​ 671,493 Income (loss) from operations ​ $ 955,796 ​ $ 856,838 ​ $ 28,311 ​ $ (514,216) ​ $ (3,112,749) ​ $ (1,786,020) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 11,472,111 ​ $ 4,191,175 ​ $ 393,804 ​ $ 1,561,469 ​ $ — ​ $ 17,618,559 Cost of goods sold ​ 8,389,404 ​ 2,273,641 ​ 157,650 ​ 1,400,675 ​ — ​ 12,221,370 Gross profit ​ 3,082,707 ​ 1,917,534 ​ 236,154 ​ 160,794 ​ — ​ 5,397,189 Selling, general, and administrative* ​ 1,832,473 ​ 1,081,847 ​ 149,924 ​ 361,342 ​ 2,058,000 ​ 5,483,586 Research and development* ​ — ​ — ​ — ​ — ​ 870,279 ​ 870,279 Income (loss) from operations ​ $ 1,250,234 ​ $ 835,687 ​ $ 86,230 ​ $ (200,548) ​ $ (2,928,279) ​ $ (956,676) ​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Chromaline ​ $ 1,676,592 ​ $ 1,916,066 IKONICS Imaging ​ 396,116 ​ 304,791 DTX ​ 35,983 ​ 13,919 AMS ​ 57,676 ​ 252,363 Unallocated ​ (47,154) ​ (52,421) ​ ​ ​ ​ ​ ​ ​ Total ​ $ 2,119,213 ​ $ 2,434,718

Basis of Presentation (Details)

Basis of Presentation (Details)	Jun. 25, 2021USD ($)$ / sharesshares
Ikonics [Member] | TeraWulf [Member]
Business Acquisition, Termination Fee	$ 10,000,000
TeraWulf [Member]
Business Acquisition, Share Price (in dollars per share) | $ / shares	$ 5
Business Acquisition, Contingent Value Right Received, Per Share (in shares) | shares	1
Business Acquisition, Shares Received, Per Share (in shares) | shares	1
Business Acquisition, Net Proceeds Received Rights, Percent	95.00%
Business Acquisition, Combined Pro Forma Equity Ownership, Percent	2.00%
Business Acquisition, Termination Fee	$ 1,200,000
TeraWulf [Member] | Selling, General and Administrative Expenses [Member]
Business Combination, Acquisition Related Costs	$ 703,000

Major Components of Inventories

Major Components of Inventories (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 1,286,151	$ 1,323,655	$ 1,667,154
Work-in-progress	399,738	428,753	419,906
Finished goods	1,140,543	1,065,458	1,449,854
Reduction to LIFO cost	(1,218,604)	(1,172,891)	(1,356,378)
Total Inventories	$ 1,607,828	$ 1,644,975	$ 2,180,536

Earnings Per Common Share (EP_3

Earnings Per Common Share (EPS) (Details) - $ / shares	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Share-based Payment Arrangement, Option [Member]
Number of Option Shares Excluded from Weighted Average Common Shares Outstanding (in shares)	13,500		13,500
Weighted Average Exercise Price Options Excluded From Weighted Average Common Share Outstanding (in dollars per share)	$ 6.18		$ 6.18
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	10,000	21,500	10,000	21,500
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount (in dollars per share)	$ 11.50	$ 7.38	$ 11.50	$ 7.38
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	87,110		87,110		54,300

Earnings Per Common Share (EP_4

Earnings Per Common Share (EPS) - Summary of Calculation of Diluted EPS (Details) - shares	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Common Share (EPS)
Weighted average common shares outstanding (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253
Dilutive effect of stock options and restricted stock units (in shares)	0	0	0	0
Weighted average common and common equivalent shares outstanding (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253

Stock-based Compensation (Detai

Stock-based Compensation (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)	23,500		17,500	19,250
Granted, Shares (in shares)	10,000	10,000	10,000	3,250
Share-based Payment Arrangement, Expense	$ 131,600	$ 7,400	$ 22,000	$ 9,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 674,000		$ 348,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	4 years		3 years
Exercise of stock options (in shares)	3,000	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 24,000
Proceeds from exercise of stock options	27,690	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	58,700
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 20,700
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	4 years
Approximation [Member]
Proceeds from exercise of stock options	$ 27,700
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	36,550	0	54,300	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)	2,400
Granted, weighted average grant date fair value (in dollars per share)	$ 11.01		$ 6.11
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			3 years
The 1995 Incentive Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)			442,750
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)	1,000		5,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)	102,157
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period (in shares)			11,750
The 1995 Incentive Stock Option Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)				102,157
The 1995 Incentive Stock Option Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	442,750
The 2019 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)	3,957		47,107
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period (in shares)	12,750		750
Granted, Shares (in shares)	23,250		13,250
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)	750
The 2019 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period (in shares)	102,157
The 2019 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			54,300
Granted, Shares (in shares)	90,850
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)	2,400

Stock-based Compensation - Assu

Stock-based Compensation - Assumptions (Details) - Share-based Payment Arrangement, Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Dividend yield	0.00%	0.00%
Expected volatility	40.30%	37.50%
Expected life of option (years) (Year)	10 years	5 years
Risk-free interest rate	1.40%	1.70%
Fair value of each option on grant date (in dollars per share)	$ 2.90	$ 2.53

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Details) - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Outstanding, Shares (in shares)	17,500	19,250	19,250
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.97	$ 11.32	$ 11.32
Granted, Shares (in shares)	10,000	10,000	10,000	3,250
Granted, Weighted Average Exercise Price (in dollars per share)	$ 11.50		$ 5.67
Exercise of stock options (in shares)	3,000	0	0	0
Exercised, Weighted Average Exercise Price (in dollars per share)	$ 9.23
Expired and forfeited, Shares (in shares)	(1,000)		(11,750)
Expired and forfeited, Weighted Average Exercise Price (in dollars per share)	$ 10.75		$ 12.99
Outstanding, Shares (in shares)	23,500		17,500	19,250
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 8.45		$ 6.97	$ 11.32
Exercisable, Shares (in shares)	5,165		5,332
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 6.54		$ 9.19

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Unvested, shares (in shares)	54,300
Unvested, weighted average grant date fair value (in dollars per share)	$ 6.11
Granted, shares (in shares)	36,550	0	54,300	0
Granted, weighted average grant date fair value (in dollars per share)	$ 11.01		$ 6.11
Vested, shares (in shares)	(1,340)
Vested, weighted average grant date fair value (in dollars per share)	$ 11.30
Forfeited or surrendered, shares (in shares)	(2,400)
Forfeited or surrendered, weighted average grant date fair value (in dollars per share)	$ 6.11
Unvested, shares (in shares)	87,110		54,300
Unvested, weighted average grant date fair value (in dollars per share)	$ 8.09		$ 6.11

Segment Information (Details)

Segment Information (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2021segment	Dec. 31, 2020
Segment Information
Number of Reportable Segments	4	4

Segment Information - Reportabl

Segment Information - Reportable Segments (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Net sales	$ 4,251,348	$ 2,572,439	$ 7,324,756	$ 6,069,631	$ 13,432,220	$ 17,618,559
Cost of goods sold	2,822,044	2,187,544	4,899,120	4,531,504	9,527,143	12,221,370
Gross profit (loss)	1,429,304	384,895	2,425,636	1,538,127	3,905,077	5,397,189
Selling general and administrative*	1,944,502	1,202,307	3,128,093	2,983,327	5,019,604	5,483,586
Research and development*	128,895	201,234	263,817	384,814	671,493	870,279
Income (loss) from operations	(644,093)	(1,018,646)	(966,274)	(1,830,014)	(1,786,020)	(956,676)
Trade receivables	1,651,035		1,651,035		2,119,213	2,434,718
Operating Segments [Member]
Trade receivables	1,651,035		1,651,035		2,119,213
Segment Reconciling Items [Member]
Net sales
Cost of goods sold
Gross profit (loss)
Selling general and administrative*	1,304,485	524,504	1,924,878	1,462,961	2,441,256	2,058,000
Research and development*	128,895	201,234	263,817	384,814	671,493	870,279
Income (loss) from operations	(1,433,380)	(725,738)	(2,188,695)	(1,847,775)	(3,112,749)	(2,928,279)
Trade receivables	(37,979)		(37,979)		(47,154)	(52,421)
Chromaline [Member]
Net sales	2,653,733	1,619,986	4,352,414	3,584,326
Cost of goods sold	1,905,738	1,407,362	3,140,523	2,825,631
Gross profit (loss)	747,995	212,624	1,211,891	758,695
Selling general and administrative*	289,928	366,136	547,930	792,355
Income (loss) from operations	458,067	(153,512)	663,961	(33,660)
Chromaline [Member] | Operating Segments [Member]
Net sales					8,475,743	11,472,111
Cost of goods sold					6,222,902	8,389,404
Gross profit (loss)					2,252,841	3,082,707
Selling general and administrative*					1,297,045	1,832,473
Research and development*
Income (loss) from operations					955,796	1,250,234
Trade receivables	1,150,630		1,150,630		1,676,592	1,916,066
Ikonics Imaging [Member]
Net sales	1,264,855	625,800	2,351,456	1,595,899
Cost of goods sold	644,071	419,985	1,193,726	897,708
Gross profit (loss)	620,784	205,815	1,157,730	698,191
Selling general and administrative*	259,219	224,573	475,755	503,435
Income (loss) from operations	361,565	(18,758)	681,975	194,756
Ikonics Imaging [Member] | Operating Segments [Member]
Net sales					3,709,318	4,191,175
Cost of goods sold					1,972,076	2,273,641
Gross profit (loss)					1,737,242	1,917,534
Selling general and administrative*					880,404	1,081,847
Research and development*
Income (loss) from operations					856,838	835,687
Trade receivables	356,216		356,216		396,116	304,791
DTX [Member]
Net sales	85,444	49,053	161,755	161,582
Cost of goods sold	34,260	24,346	77,052	76,092
Gross profit (loss)	51,184	24,707	84,703	85,490
Selling general and administrative*	32,001	30,059	62,040	64,432
Income (loss) from operations	19,183	(5,352)	22,663	21,058
DTX [Member] | Operating Segments [Member]
Net sales					294,929	393,804
Cost of goods sold					140,866	157,650
Gross profit (loss)					154,063	236,154
Selling general and administrative*					125,752	149,924
Research and development*
Income (loss) from operations					28,311	86,230
Trade receivables	26,759		26,759		35,983	13,919
AMS [Member]
Net sales	247,316	277,600	459,131	727,824
Cost of goods sold	237,975	335,851	487,819	732,073
Gross profit (loss)	9,341	(58,251)	(28,688)	(4,249)
Selling general and administrative*	58,869	57,035	117,490	160,144
Income (loss) from operations	(49,528)	$ (115,286)	(146,178)	$ (164,393)
AMS [Member] | Operating Segments [Member]
Net sales					952,230	1,561,469
Cost of goods sold					1,191,299	1,400,675
Gross profit (loss)					(239,069)	160,794
Selling general and administrative*					275,147	361,342
Research and development*
Income (loss) from operations					(514,216)	(200,548)
Trade receivables	$ 155,409		$ 155,409		$ 57,676	$ 252,363

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Percent, Total	0.10%	0.00%	1.80%	12.80%
Income Tax Expense (Benefit), Total	$ 823	$ 0	$ (19,524)	$ (238,929)	$ (210,000)	$ (172,000)
Unrecognized Tax Benefits, Ending Balance	0		0		$ 0
Approximation [Member]
Income Tax Expense (Benefit), Total	$ 1,000	$ 0	$ 19,000	$ 239,000

Long-Term Debt (Details)

Long-Term Debt (Details)	Apr. 01, 2021USD ($)	Apr. 29, 2016USD ($)ft²	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Apr. 01, 2016USD ($)
Tax Exempt Industrial Revenue Bonds Amount Sold to Bank						$ 3,415,000
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate			1.80%
Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 2,050,000	$ 2,050,000
Long-term Line of Credit, Total			$ 0	$ 0	$ 0
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate				1.80%
Loan [Member]
Debt Instrument, Periodic Payment, Total		$ 18,000
Debt Instrument, Interest Rate, Stated Percentage		2.60%
Debt Issuance Costs, Gross		$ 139,000
Debt Instrument, Interest Rate, Effective Percentage			3.23%	3.23%
Repayments of Debt	$ 2,700,000
Interest Paid, Including Capitalized Interest, Operating and Investing Activities, Total	6,100
Write off of Deferred Debt Issuance Cost	$ 82,000
Loan [Member] | Building [Member]
Area of Real Estate Property (Square Foot) | ft²		27,300
Duluth Economic Development Authority [Member]
Tax Exempt Industrial Revenue Bonds Amount Sold to Bank						$ 3,415,000

BALANCE SHEETS

BALANCE SHEETS - USD ($)	Dec. 31, 2020	Dec. 31, 2019
CURRENT ASSETS:
Cash	$ 3,693,845	$ 963,649
Short-term investments	0	2,205,000
Trade receivables, less allowance of $55,000 in 2020 and $58,000 in 2019	2,119,213	2,434,718
Inventories	1,644,975	2,180,536
Prepaid expenses and other assets	125,969	906,916
Income taxes receivable	219,451	1,369
Total current assets	7,803,453	8,692,188
PROPERTY, PLANT, AND EQUIPMENT, at cost:
Land and building	9,556,586	9,556,984
Machinery and equipment	5,263,586	5,198,784
Office equipment	1,417,219	1,402,369
Vehicles	245,674	245,674
Property, plant, and equipment, Gross	16,483,065	16,403,811
Less accumulated depreciation	(9,094,702)	(8,487,827)
Total property, plant and equipment at cost, net	7,388,363	7,915,984
PATENTS, less accumulated amortization of $207,399 in 2020 and $181,609 in 2019	243,583	271,369
Total assets	15,435,399	16,879,541
CURRENT LIABILITIES
Current portion of long-term debt	2,688,396	133,287
Accounts payable	459,836	761,641
Accrued compensation	279,755	382,303
Other accrued liabilities	168,066	657,255
Total current liabilities	3,596,053	1,934,486
LONG-TERM LIABILITIES
Long-term debt, less current portion		2,688,357
Total liabilities	3,596,053	4,622,843
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY
Preferred stock, par value $.10 per share; authorized 250,000 shares; issued none	0	0
Common stock, par value $.10 per share; authorized 4,750,000 shares; issued and outstanding 1,980,694 shares in 2021 and 1,976,354 in 2020	197,635	197,635
Additional paid-in-capital	2,743,930	2,721,962
Retained earnings	8,897,781	9,337,101
Total stockholders' equity	11,839,346	12,256,698
Total liabilities and stockholders' equity	$ 15,435,399	$ 16,879,541

BALANCE SHEETS (Parentheticals)

BALANCE SHEETS (Parentheticals) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 54,000	$ 55,000	$ 58,000
Intangible assets, accumulated amortization	$ 205,697	$ 207,399	$ 181,609
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10	$ 0.10
Preferred stock, authorized (in shares)	250,000	250,000	250,000
Preferred stock, issued (in shares)	0	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	4,750,000	4,750,000	4,750,000
Common stock, share issued (in shares)	1,980,694	1,976,354	1,976,354
Common stock, share outstanding (in shares)	1,980,694	1,976,354	1,976,354

STATEMENTS OF OPERATIONS

STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
NET SALES	$ 4,251,348	$ 2,572,439	$ 7,324,756	$ 6,069,631	$ 13,432,220	$ 17,618,559
COST OF GOODS SOLD	2,822,044	2,187,544	4,899,120	4,531,504	9,527,143	12,221,370
GROSS PROFIT	1,429,304	384,895	2,425,636	1,538,127	3,905,077	5,397,189
SELLING, GENERAL AND ADMINISTRATIVE EXPENSES	1,944,502	1,202,307	3,128,093	2,983,327	5,019,604	5,483,586
RESEARCH AND DEVELOPMENT EXPENSES	128,895	201,234	263,817	384,814	671,493	870,279
LOSS FROM OPERATIONS	(644,093)	(1,018,646)	(966,274)	(1,830,014)	(1,786,020)	(956,676)
INTEREST EXPENSE	(82,498)	(24,623)	(102,340)	(46,107)	(86,561)	(90,058)
OTHER INCOME	5,138	1,766	5,175	8,683	1,223,261	61,176
LOSS BEFORE INCOME TAXES	(721,453)	(1,041,503)	(1,063,439)	(1,867,438)	(649,320)	(985,558)
INCOME TAX EXPENSE (BENEFIT)	823	0	(19,524)	(238,929)	(210,000)	(172,000)
NET LOSS	$ (722,276)	$ (1,041,503)	$ (1,043,915)	$ (1,628,509)	$ (439,320)	$ (813,558)
Earnings Per Common Share (EPS)
Basic (in dollars per share)	$ (0.37)	$ (0.53)	$ (0.53)	$ (0.82)	$ (0.22)	$ (0.41)
Diluted (in dollars per share)	$ (0.37)	$ (0.53)	$ (0.53)	$ (0.82)	$ (0.22)	$ (0.41)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
Basic (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253
Diluted (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253

STATEMENTS OF STOCKHOLDERS' E_2

STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)	Common Stock	Additional Paid-in Capital	Retained Earnings	Total
BALANCE (in shares)	1,983,553
BALANCE at Dec. 31, 2018	$ 198,355	$ 2,723,024	$ 10,189,651	$ 13,111,030
Net loss			(813,558)	(813,558)
Common stock repurchased	$ (720)	(9,883)	(38,992)	$ (49,595)
Common stock repurchased (in shares)	(7,199)			(7,199)
Stock based compensation		8,821		$ 8,821
BALANCE at Dec. 31, 2019	$ 197,635	2,721,962	9,337,101	$ 12,256,698
BALANCE (in shares)	1,976,354			1,976,354
Net loss	$ 0	0	(1,628,509)	$ (1,628,509)
Stock based compensation	0	7,376	0	7,376
BALANCE at Jun. 30, 2020	197,635	2,729,338	7,708,592	10,635,565
BALANCE at Dec. 31, 2019	197,635	2,721,962	9,337,101	12,256,698
Net loss			(439,320)	$ (439,320)
Common stock repurchased (in shares)				0
Stock based compensation		21,968		$ 21,968
BALANCE at Dec. 31, 2020	$ 197,635	2,743,930	8,897,781	11,839,346
BALANCE (in shares)	1,976,354
BALANCE at Mar. 31, 2020	$ 197,635	2,725,650	8,750,095	11,673,380
Net loss	0	0	(1,041,503)	(1,041,503)
Stock based compensation	0	3,688	0	3,688
BALANCE at Jun. 30, 2020	$ 197,635	2,729,338	7,708,592	$ 10,635,565
BALANCE (in shares)	1,976,354
BALANCE (in shares)	1,976,354			1,976,354
BALANCE at Dec. 31, 2020	$ 197,635	2,743,930	8,897,781	$ 11,839,346
Net loss	0	0	(1,043,915)	(1,043,915)
Stock based compensation	0	131,604	0	131,604
BALANCE at Jun. 30, 2021	$ 198,069	2,902,790	7,853,866	10,954,725
BALANCE (in shares)	1,977,104
BALANCE at Mar. 31, 2021	$ 197,710	2,787,733	8,576,142	11,561,585
Net loss	0	0	(722,276)	(722,276)
Stock based compensation	0	94,117	0	94,117
BALANCE at Jun. 30, 2021	$ 198,069	$ 2,902,790	$ 7,853,866	$ 10,954,725
BALANCE (in shares)	1,980,694			1,980,694

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (439,320)	$ (813,558)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	661,565	639,997
Amortization	36,489	43,014
Stock based compensation	21,968	8,821
Forgiveness on paycheck protection loan	(1,214,500)
Net gain on sale and disposal of equipment	(2,325)	(8,482)
Deferred income taxes		(183,000)
Loss on intangible asset abandonment	16,906	92,833
Changes in working capital components:
Trade receivables	315,505	(219,503)
Inventories	535,561	(133,948)
Prepaid expenses and other assets	780,947	(531,554)
Income tax receivable	(218,082)	1,399
Accounts payable	(301,805)	114,113
Accrued expenses	(591,737)	512,837
Net cash provided by (used in) operating activities	(398,828)	(477,031)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(149,916)	(478,353)
Proceeds from sales of equipment	18,297	15,596
Purchases of patents	(14,910)	(19,665)
Purchases of short-term investments		(5,635,000)
Proceeds on sale of short-term investments	2,205,000	6,125,000
Net cash (used in) provided by investing activities	2,058,471	7,578
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from paycheck protection program loan	1,214,500
Principal payments on long-term debt	(143,947)	(140,440)
Repurchase of common stock		(49,595)
Net cash (used in) provided by financing activities	1,070,553	(190,035)
NET (DECREASE) INCREASE IN CASH	2,730,196	(659,488)
CASH AT BEGINNING OF PERIOD	963,649	1,623,137
CASH AT END OF PERIOD	3,693,845	963,649
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest	75,227	79,008
Net cash received (paid for) income taxes, net	$ 8,082	$ 9,457

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Description of Business and Foreign Export Sales The full extent of the effect of the COVID-19 pandemic on the Company’s customers, supply chain and business is difficult to assess at this time although the Company’s 2020 results of operations were adversely affected. The Company has developed a plan to mitigate the impact of COVID-19 which includes the implementation of a series of specific and identified cost reductions, in addition to actions already taken, including further reducing its direct and indirect operating costs. The impact of COVID-19 on the Company’s operating results will depend on future developments, which are highly uncertain and difficult to predict, including governmental and business reactions to the pandemic. Based on the Company’s current cash position, and expected future cash flows, the Company believes it will have sufficient cash to repay its entire $2.7 million loan and continue to fund its operations beyond twelve months from the date of the issuance of the financial statements The Company has evaluated subsequent events occurring after the date of the financial statements for events requiring recording or disclosure in the financial statements. As a result of the novel strain of COVID-19 pandemic effect on the Company’s business as well as the businesses of its customers and suppliers, a significant decline in the Company’s business has occurred and that decline is expected to continue. Although the Company continues to operate, the Company has experienced a significant decrease in sales activity, and the future financial impact and duration is difficult to reasonably estimate at this time. Foreign sales approximated 29.7% and 29.4% of net sales in 2020 and 2019, respectively. Foreign receivables are comprised primarily of open credit arrangements with terms ranging from 30 to 90 days. No single customer or foreign country represented greater than 10% of net sales in 2020 or in 2019. The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. A summary of the Company’s significant accounting policies follows: Cash Equivalents States government agencies or instrumentalities, repurchase agreements fully collateralized by the United States Treasury, and United States government securities. The Company maintains its cash balances primarily in two financial institutions. As of December 31, 2020, the balance at both institutions exceeded the Federal Deposit Insurance Corporation coverage. Short-Term Investments Inventories The major components of inventories, net of inventory reserve, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Raw materials ​ $ 1,323,655 ​ $ 1,667,154 Work-in-progress ​ 428,753 ​ 419,906 Finished goods ​ 1,065,458 ​ 1,449,854 Reduction to LIFO cost ​ (1,172,891) ​ (1,356,378) ​ ​ ​ ​ ​ ​ ​ Total Inventories ​ $ 1,644,975 ​ $ 2,180,536 ​ Property, Plant and Equipment ​ ​ ​ ​ ​ Years Buildings ​ 15 – 40 Machinery and equipment 5 – 10 Office equipment 3 – 10 Vehicles ​ 3 ​ Patents — Impairment of Long-lived Assets — Fair Value of Financial Instruments Revenue recognition certain customers. Revenue from all customers is recognized when a performance obligation is satisfied by transferring control of a distinct good or service to a customer. Individually promised goods and services in a contract are considered a distinct performance obligation and accounted for separately if the customer can benefit from the individual good or service on its own or with other resources that are readily available to the customer and the good or service is separately identifiable from other promises in the arrangement. When an arrangement includes multiple performance obligations, the consideration is allocated between the performance obligations in proportion to their estimated standalone selling price. Costs related to products delivered are recognized in the period incurred, unless criteria for capitalization of costs are met. Costs of revenues consist primarily of direct labor, manufacturing overhead, materials and components. The Company does not incur significant upfront costs to obtain a contract. If costs to obtain a contract were to become material, the costs would be recorded as an asset and amortized to expense in a manner consistent with the related recognition of revenue. The Company excludes from revenue governmental assessed and imposed taxes on revenue transactions that are invoiced to customers. The Company includes freight billed to customers in revenue. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold. The timing of revenue recognition, billings and cash collections results in accounts receivable on the balance sheet. Performance obligations The Company sells its products to both distributors and end-users. Each unit of product delivered under a customer order represents a distinct and separate performance obligation as the customer can benefit from each unit on its own or with other resources that are readily available to the customer and each unit of product is separately identifiable from other products in the arrangement. The transaction price for the Company’s products is the invoiced amount. The Company does not have variable consideration in the form of refunds, credits, rebates, price concessions, pricing incentives or other items impacting transaction price. The purchase order pricing in arrangements with customers is deemed to approximate standalone selling price; therefore, the Company does not need to allocate proceeds on a relative standalone selling price allocation between performance obligations. The Company does not disclose information about remaining performance obligations that have original expected durations of one year or less. There are no material obligations that extend beyond one year. Revenue is recognized when transfer of control occurs as defined by the terms in the customer agreement. The Company immediately recognizes incidental items that are immaterial in the context of the contract. The Company does not have any significant financing components in its customer arrangements as payment is received at or shortly after the point of sale, generally thirty to ninety days. The Company estimates returns based on an analysis of historical experience if the right to return products is granted to its customers. The Company does not record a return asset as non-conforming products are generally not returned. The Company’s return policy does not vary by geography. The customer has no rotation or price protection rights. Trade receivables. receivable balance for customers paying in a foreign currency. These balances are adjusted to each quarter or year-end spot rate. Foreign currency transactions and translation adjustments did not have a significant effect on the Balance Sheets, the Statements of Operations, Stockholders’ Equity or Cash Flows for 2020 and 2019. Sales commissions. Product warranties. International revenue. Deferred Taxes The Company follows the accounting standard on accounting for uncertainty in income taxes, which addresses the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the financial statements. Under this guidance, the Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement. The guidance on accounting for uncertainty in income taxes also addresses derecognition, classification, interest and penalties on income taxes, and accounting in interim periods. Earnings Per Share (EPS) Shares used in the calculation of diluted EPS are summarized below: ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Weighted average common shares outstanding ​ 1,976,354 ​ 1,980,253 Dilutive effect of stock options and restricted stock units — ​ — Weighted average common and common equivalent shares outstanding 1,976,354 ​ 1,980,253 ​ If the Company was in a net income position at December 31, 2020, all 17,500 options outstanding with a weighted average exercise price of $6.97 would have remained excluded from the computation of weighted average common and common equivalent shares outstanding as the options were anti-dilutive. Restricted stock units of approximately 54,300 shares for the year-end December 31, 2020 would have remained excluded from the computation of weighted average common and common equivalent shares outstanding as they were anti-dilutive due to the amount of weighted-average unrecognized compensation related to these grants. At December 31, 2019, options to purchase 19,250 shares of common stock with a weighted average exercise price of $11.32 were outstanding, but were excluded from the computation of common share equivalents because they were anti-dilutive. Employee Stock Plan — Recent Accounting Pronouncements — Use of Estimates

INCOME TAXES_2

INCOME TAXES	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Income Taxes
INCOME TAXES	6. Income Taxes The Company records its interim provision for income taxes by applying its estimated annual effective tax rate to the year-to-date pre-tax income and adjusting for discrete tax items recorded in the period. Deferred income taxes result from temporary differences between the reporting of amounts for financial statement purposes and income tax purposes. These differences relate primarily to different methods used for income tax reporting purposes, including for depreciation and amortization, warranty and vacation accruals, and deductions related to allowances for doubtful accounts receivable and inventory reserves. The provision for income taxes included current federal and state income tax expense, as well as deferred federal and state income tax expense. Management assesses the available positive and negative evidence to estimate whether sufficient future taxable income will be generated to permit use of the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss incurred over the three-year period ended June 30, 2021. Such objective evidence limits the ability to consider other subjective evidence, such as our projections for future growth. On the basis of this evaluation, as of June 30, 2021, a full valuation allowance has been recorded to reserve for deferred tax assets entirely, which are not expected to be realized. The valuation allowance will be reevaluated on a quarterly basis and may change if estimates of future taxable income during the carryforward period is increased or if objective negative evidence in the form of cumulative losses is no longer present and additional weight is given to subjective evidence such as our projections for growth The effective tax rate for the three months ended June 30, 2021 was a benefit of 0.1%, compared to an effective tax rate 0.0% for the three months ended June 30, 2020. The Company recorded an income tax benefit of $1,000 and a benefit of $0 for the three months ended June 30, 2021 and 2020, respectively. The effective tax rate for the six months ended June 30, 2021 was a benefit of 1.8%, compared to a benefit 12.8% for the six months ended June 30, 2020. The primary driver of the change in the Company’s effective tax rate is attributable to additional benefit from an net operating loss carryback claim recorded in the prior year. The Company recorded an income tax benefit of $19,000 and a benefit of $239,000 for the six months ended June 30, 2021 and 2020, respectively. The Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority is more-likely -than-not to sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the condensed consolidated financial statements is the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant tax authority. As of June 30, 2021, the Company has no unrecognized tax benefits. This Company is not currently under examination in any jurisdiction. In the event of any future tax assessments, the Company has elected to record the income taxes and any related interest and penalties as income tax expense on the statement of operations.	2. INCOME TAXES Income tax benefit for the years ended December 31, 2020 and 2019 consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Current: ​ ​ ​ ​ ​ ​ Federal ​ $ (216,000) ​ $ — State ​ ​ 6,000 ​ ​ 11,000 ​ ​ ​ (210,000) ​ ​ 11,000 Deferred — Federal ​ ​ — ​ ​ (183,000) ​ ​ $ (210,000) ​ $ (172,000) ​ The expected (benefit) provision for income taxes, computed by applying the U.S. federal income tax rate of 21% to income (loss) before taxes, is reconciled to income benefit as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 Expected provision for federal income taxes ​ $ (136,000) ​ $ (207,000) State income taxes, net of federal benefit ​ (24,000) ​ (7,000) Permanent items ​ (249,000) ​ 11,000 Research and development credit ​ (23,000) ​ (29,000) Change in valuation allowance ​ 440,000 ​ 51,000 Change in tax law allowing NOL carryback claim ​ (217,000) ​ — Prior year true-ups and other ​ (1,000) ​ 9,000 ​ ​ $ (210,000) ​ $ (172,000) ​ Net deferred tax liabilities consist of the following as of December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Deferred tax liabilities: ​ ​ ​ ​ ​ ​ Accrued vacation ​ $ 33,000 ​ $ 21,000 Inventories reserve ​ 17,000 ​ 42,000 Allowance for doubtful accounts ​ 2,000 ​ 3,000 Allowance for sales returns ​ 10,000 ​ 10,000 Research and development credit carryforward ​ 285,000 ​ 245,000 Accrued self-insured medical ​ — ​ 3,000 Property and equipment ​ (257,000) ​ (295,000) Patents ​ (50,000) ​ (53,000) Net operating loss ​ 411,000 ​ 230,000 Other ​ 17,000 ​ 8,000 Valuation allowance ​ (468,000) ​ (214,000) Net deferred tax liabilities ​ $ — ​ $ — ​ As of December 31, 2020, the Company has federal net operating loss carry-forwards and research and development credit carryovers of $1,847,000 and $104,000, respectively, and begin expiring in 2037. The Company’s state net operating loss carryforwards and research and development credit carryovers at December 31, 2020 total $468,000 and $214,000, respectively, and begin expiring in 2026. The Company is subject to federal and state taxation. As of December 31, 2020, with few exceptions, the Company is no longer subject to examination prior to tax year 2017. In accounting for uncertainty in income taxes, we recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more likely than not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority. As of December 31, 2020, the Company does not have any unrecognized tax benefits. The Company recognizes interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. We do not expect any material changes in our unrecognized tax benefits over the next 12 months. The Company establishes a valuation allowance to reduce the deferred tax assets when it is more likely than not that a deferred tax asset will not be realizable. On the basis of this evaluation, as of December 31, 2020 and 2019, a full valuation allowance has been recorded to reserve for deferred tax assets, which are not expected to be realized.

INTANGIBLE ASSETS

INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2020
INTANGIBLE ASSETS
INTANGIBLE ASSETS	3. INTANGIBLE ASSETS Intangible assets consist of patents, and patent applications. Capitalized patent application costs are included with patents. Intangible assets are amortized on a straight-line basis over their estimated useful lives or terms of their agreement, whichever is shorter. The Company wrote off costs related to abandoned patent applications of $17,000 $93,000 Intangible assets at December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ Gross ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ Carrying ​ Accumulated ​ Carrying ​ Accumulated ​ Amount Amortization Amount Amortization Amortized intangible assets: ​ ​ ​ ​ Patents ​ $ 450,982 ​ $ (207,399) ​ $ 452,978 ​ $ (181,609) ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Aggregate amortization expense: ​ ​ ​ ​ ​ ​ For the years ended December 31 ​ $ 25,790 ​ $ 31,869 ​ Estimated amortization expense for the years ending 31: ​ ​ ​ ​ ​ 2021 $ 25,000 2022 ​ 25,000 2023 ​ 25,000 2024 ​ 24,000 2025 ​ 24,000 Thereafter ​ 67,000 ​ In connection with a license agreement, the Company has agreed to pay royalties ranging from 3% to 5% on the sales of products subject to the agreement. The Company incurred $8,000 and $10,000 of expense under these agreements during 2020 and 2019, respectively, which are included in selling, general and administrative expenses in the Statements of Operations.

RETIREMENT PLAN

RETIREMENT PLAN	12 Months Ended
	Dec. 31, 2020
RETIREMENT PLAN
RETIREMENT PLAN	4. RETIREMENT PLAN The Company has established a salary deferral plan under Section 401(k) of the Internal Revenue Code. Such deferrals accumulate on a tax-deferred basis until the employee withdraws the funds. Historically, the Company has contributed up to 5% of each eligible employee’s compensation. As part of cost reduction efforts in 2020 the Company temporarily suspended its 5% contribution in 2020. Total retirement expense for the years ended December 31, 2020 and 2019 was approximately $120,000 and $241,000, respectively. The Company anticipates it will resume at least a portion of its 5% 401(k) contribution in 2021 as business conditions allow.

SEGMENT INFORMATION_2

SEGMENT INFORMATION	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Segment Information
SEGMENT INFORMATION	5. Segment Information The Company’s reportable segments are strategic business units that offer different products and have varied customer bases. There are four reportable segments: Chromaline, IKONICS Imaging, Digital Texturing (DTX) and Advanced Material Solutions (AMS). Chromaline sells screen printing film, emulsions, and inkjet receptive film primarily to distributors and some end users. IKONICS Imaging sells photo resistant film, art supplies, glass, and related abrasive etching equipment to both end users and distributors. AMS provides sound deadening and weight reduction technology to the aerospace industry along with products and services for etched composites, ceramics, glass and silicon wafers. DTX includes products and customers related to patented and proprietary inkjet technology used for mold texturing and prototyping. The accounting policies applied to determine the segment information are the same as those described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. Management evaluates the performance of each segment based on the components of divisional income (loss). Assets and liabilities are not allocated to segments, except for trade receivables. Financial information with respect to the reportable segments follows: For the three months ended June 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 2,653,733 ​ $ 1,264,855 ​ $ 85,444 ​ $ 247,316 ​ $ — ​ $ 4,251,348 Cost of goods sold ​ 1,905,738 ​ 644,071 ​ 34,260 ​ 237,975 ​ — ​ 2,822,044 Gross profit ​ 747,995 ​ 620,784 ​ 51,184 ​ 9,341 ​ — ​ 1,429,304 Selling general and administrative* ​ 289,928 ​ 259,219 ​ 32,001 ​ 58,869 ​ 1,304,485 ​ 1,944,502 Research and development* ​ — ​ — ​ — ​ — ​ 128,895 ​ 128,895 Income (loss) from operations ​ $ 458,067 ​ $ 361,565 ​ $ 19,183 ​ $ (49,528) ​ $ (1,433,380) ​ $ (644,093) ​ For the three months ended June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 1,619,986 ​ $ 625,800 ​ $ 49,053 ​ $ 277,600 ​ $ — ​ $ 2,572,439 Cost of goods sold ​ 1,407,362 ​ 419,985 ​ 24,346 ​ 335,851 ​ — ​ 2,187,544 Gross profit (loss) ​ 212,624 ​ 205,815 ​ 24,707 ​ (58,251) ​ — ​ 384,895 Selling general and administrative * ​ 366,136 ​ 224,573 ​ 30,059 ​ 57,035 ​ 524,504 ​ 1,202,307 Research and development* ​ — ​ — ​ — ​ — ​ 201,234 ​ 201,234 Loss from operations ​ $ (153,512) ​ $ (18,758) ​ $ (5,352) ​ $ (115,286) ​ $ (725,738) ​ $ (1,018,646) ​ For the six months ended June 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 4,352,414 ​ $ 2,351,456 ​ $ 161,755 ​ $ 459,131 ​ $ — ​ $ 7,324,756 Cost of goods sold ​ 3,140,523 ​ 1,193,726 ​ 77,052 ​ 487,819 ​ — ​ 4,899,120 Gross profit (loss) ​ 1,211,891 ​ 1,157,730 ​ 84,703 ​ (28,688) ​ — ​ 2,425,636 Selling general and administrative* ​ 547,930 ​ 475,755 ​ 62,040 ​ 117,490 ​ 1,924,878 ​ 3,128,093 Research and development* ​ — ​ — ​ — ​ — ​ 263,817 ​ 263,817 Income (loss) from operations ​ $ 663,961 ​ $ 681,975 ​ $ 22,663 ​ $ (146,178) ​ $ (2,188,695) ​ $ (966,274) ​ For the six months ended June 30, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 3,584,326 ​ $ 1,595,899 ​ $ 161,582 ​ $ 727,824 ​ $ — ​ $ 6,069,631 Cost of goods sold ​ 2,825,631 ​ 897,708 ​ 76,092 ​ 732,073 ​ — ​ 4,531,504 Gross profit (loss) ​ 758,695 ​ 698,191 ​ 85,490 ​ (4,249) ​ — ​ 1,538,127 Selling general and administrative* ​ 792,355 ​ 503,435 ​ 64,432 ​ 160,144 ​ 1,462,961 ​ 2,983,327 Research and development* ​ — ​ — ​ — ​ — ​ 384,814 ​ 384,814 Income (loss) from operations ​ $ (33,660) ​ $ 194,756 ​ $ 21,058 ​ $ (164,393) ​ $ (1,847,775) ​ $ (1,830,014) * The Company does not allocate all selling, general and administrative expenses or any research and development expenses to its operating segments for internal reporting. Trade receivables by segment as of June 30, 2021 and December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Jun 30, 2021 Dec 31, 2020 Chromaline ​ $ 1,150,630 ​ $ 1,676,592 IKONICS Imaging ​ 356,216 ​ 396,116 DTX ​ 26,759 ​ 35,983 AMS ​ 155,409 ​ 57,676 Unallocated ​ (37,979) ​ (47,154) Total ​ $ 1,651,035 ​ $ 2,119,213 ​	5. SEGMENT INFORMATION The Company’s reportable segments are strategic business units that offer different products and have varied customer bases. There are four reportable segments: Chromaline, IKONICS Imaging, Digital Texturing (DTX) and Advanced Material Solutions (AMS). Chromaline sells screen printing film, emulsions, and inkjet receptive film primarily to distributors and some end users. IKONICS Imaging sells photo resistant film, art supplies, glass, and related abrasive etching equipment to both end users and distributors. AMS provides sound deadening and weight reduction technology to the aerospace industry along with products and services for etched composites, ceramics, glass and silicon wafers. DTX includes products and customers related to patented and proprietary inkjet technology used for mold texturing and prototyping.The accounting policies of the segments are the same as those described in the summary of significant accounting policies included in Note 1. Management evaluates the performance of each segment based on the components of divisional income, and does not allocate assets and liabilities to segments except for trade receivables. Financial information with respect to the reportable segments follows: For the year ended December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline ​ Imaging ​ DTX ​ AMS ​ Unalloc. ​ Total Net sales ​ $ 8,475,743 ​ $ 3,709,318 ​ $ 294,929 ​ $ 952,230 $ — ​ $ 13,432,220 Cost of goods sold ​ 6,222,902 ​ 1,972,076 ​ 140,866 ​ 1,191,299 ​ — ​ 9,527,143 Gross profit (loss) ​ 2,252,841 ​ 1,737,242 ​ 154,063 ​ (239,069) ​ — ​ 3,905,077 Selling, general, and administrative* ​ 1,297,045 ​ 880,404 ​ 125,752 ​ 275,147 ​ 2,441,256 ​ 5,019,604 Research and development* ​ — ​ — ​ — ​ — ​ 671,493 ​ 671,493 Income (loss) from operations ​ $ 955,796 ​ $ 856,838 ​ $ 28,311 ​ $ (514,216) ​ $ (3,112,749) ​ $ (1,786,020) ​ For the year ended December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 11,472,111 ​ $ 4,191,175 ​ $ 393,804 ​ $ 1,561,469 ​ $ — ​ $ 17,618,559 Cost of goods sold ​ 8,389,404 ​ 2,273,641 ​ 157,650 ​ 1,400,675 ​ — ​ 12,221,370 Gross profit ​ 3,082,707 ​ 1,917,534 ​ 236,154 ​ 160,794 ​ — ​ 5,397,189 Selling, general, and administrative* ​ 1,832,473 ​ 1,081,847 ​ 149,924 ​ 361,342 ​ 2,058,000 ​ 5,483,586 Research and development* ​ — ​ — ​ — ​ — ​ 870,279 ​ 870,279 Income (loss) from operations ​ $ 1,250,234 ​ $ 835,687 ​ $ 86,230 ​ $ (200,548) ​ $ (2,928,279) ​ $ (956,676) * The Company does not allocate all general and administrative expenses or any research and development expenses to its operating segments for internal reporting. Trade receivables by segment as of December ​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Chromaline ​ $ 1,676,592 ​ $ 1,916,066 IKONICS Imaging ​ 396,116 ​ 304,791 DTX ​ 35,983 ​ 13,919 AMS ​ 57,676 ​ 252,363 Unallocated ​ (47,154) ​ (52,421) ​ ​ ​ ​ ​ ​ ​ Total ​ $ 2,119,213 ​ $ 2,434,718 ​

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Stock-Based Compensation
STOCKHOLDERS' EQUITY	4. Stock-Based Compensation The Company maintains the 2019 Equity Incentive Plan (the “2019 Plan”). The 2019 Plan replaced the 1995 Incentive Stock Option Plan (the “1995 Plan) upon its ratification by shareholders in April 2019. The 1995 plan authorized the issuance of up to 442,750 shares of common stock through grants of restricted stock units and options. Of those shares, 1,000 were subject to outstanding options as of June 30, 2021. Awards granted under the 1995 Plan will remain in effect until they are exercised or expire according to their terms. At the time the 2019 Plan was approved, there were 102,157 shares reserved for future grants under the 1995 Plan which will no longer be available for future grants. Under the terms of the 2019 Plan, the number of shares of common stock that may be the subject of awards and issued under the 2019 Plan was initially set at 102,157. Subsequent to the approval of the 2019 Plan, 12,750 outstanding options granted under the 1995 Plan were forfeited. Under the terms of the 2019 Plan, those forfeited options are added back to the 2019 Plan reserve pool. As of June 30, 2021, 90,850 restricted stock units (RSUs) and 23,250 options have been granted under the 2019 Plan, of which 750 stock options and 2,400 RSUs have been forfeited, bringing the number of shares of common stock available for future awards under the 2019 Plan to 3,957. The Company charged compensation cost of approximately $131,600 against the loss for the six months ended June 30, 2021 and approximately $7,400 for the six months ended June 30, 2020. As of June 30, 2021, there was approximately $674,000 of unrecognized compensation cost related to unvested share-based compensation awards. That cost is expected to be recognized over the next four years . The Company receives a tax deduction for certain stock option exercises during the period in which the options are exercised, generally for the excess of the market price at the time the stock options are exercised over the exercise price of the options, which increases additional paid in capital and reduces income taxes payable. Proceeds from the exercise of 3,000 stock options with an intrinsic value of approximately $24,000 were approximately $27,700 for the six months ended June 30, 2021. No stock options were exercised during the six months ended June 30, 2020. There were 10,000 options granted during the six months ended June 30, 2021 and 2020. The fair value of options granted during the six months ended June 30, 2021 and 2020 were estimated using the Black Scholes option pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 Dividend yield ​ — ​ — ​ Expected volatility ​ 51.6 % ​ 40.3 % Expected life of option (years) ​ 10 ​ 10 ​ Risk-free interest rate ​ 0.5 % ​ 1.4 % Fair value of each option on grant date ​ $ 6.84 ​ $ 2.90 ​ ​ Stock option activity during the six months ended June 30, 2021 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2021 17,500 ​ $ 6.97 Granted 10,000 ​ 11.50 Exercised (3,000) ​ 9.23 Expired and forfeited (1,000) ​ 10.75 Outstanding at June 30, 2021 23,500 ​ $ 8.45 Exercisable at June 30, 2021 5,165 ​ $ 6.54 ​ The aggregate intrinsic value of all options outstanding and for those exercisable at June 30, 2021 was approximately $58,700 and $20,700, respectively. There were 36,550 RSUs granted during the six months ended June 30, 2021. The shares underlying the awards were assigned a weighted average value of $11.01 per share, based on the closing price of the Company’s common stock on the date of grants. These awards scheduled vesting period ranges from some awards vesting at the time of the grant up to four years . No RSUs were granted during the six months ended June 30, 2020. RSU activity during the six months ended June 30, 2021 is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested shares at January 1, 2021 54,300 ​ $ 6.11 Granted 36,550 ​ 11.01 Vested (1,340) ​ 11.30 Forfeited or surrendered (2,400) ​ 6.11 Unvested shares at June 30, 2021 87,110 ​ 8.09 ​	6. STOCKHOLDERS’ EQUITY The Company maintains the 2019 Equity Incentive Plan (the “2019 Plan”). The 2019 Plan replaced the 1995 Incentive Stock Option Plan (the “1995 Plan) upon its ratification by shareholders in April 2019. The 1995 plan authorized the issuance of up to 442,750 shares of common stock through grants of restricted stock units and options. Of those shares, 5,000 were subject to outstanding options as of December 31, 2020. Awards granted under the 1995 Plan will remain in effect until they are exercised or expire according to their terms. At the time the 2019 Plan was approved, there were 102,157 shares reserved for future grants under the 1995 Plan which will no longer be available for future grants. Under the terms of the 2019 Plan, the number of shares of common stock that may be the subject of awards and issued under the 2019 Plan was initially set at 102,157. Subsequent to the approval of the 2019 Plan, 11,750 outstanding options granted under the 1995 Plan were forfeited. Under the terms of the 2019 Plan, those forfeited options are added back to the 2019 Plan reserve pool. As of December 31, 2020, 54,300 restricted stock units (RSUs) and 13,250 options have been granted under the 2019 Plan, of which 750 stock options have been forfeited, bringing the number of shares of common stock available for future awards under the 2019 Plan to 47,107. The Company charged compensation expense of $22,000 and $9,000 against the loss in 2020 and 2019, respectively. As of December 31, 2020, there was approximately $348,000 of unrecognized compensation expense related to unvested share-based compensation awards granted which is expected to be recognized over the next three No stock options were exercised in 2020 or 2019 The fair value of options granted was estimated using the Black-Scholes option pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Dividend yield ​ 0 ​ 0 ​ Expected volatility ​ 40.3 % ​ 37.5 % Expected life of option (years) ​ 10 ​ 5 ​ Risk-free interest rate ​ 1.4 % ​ 1.7 % Fair value of each option on grant date ​ $ 2.90 ​ $ 2.53 ​ ​ There were 10,000 and 3,250 options granted during 2020 and 2019, respectively. A summary of the status of the Company’s stock option plan as of December 31, 2020 and changes during the year then ended is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2020 19,250 ​ $ 11.32 Granted 10,000 ​ 5.67 Exercised — ​ — Expired and forfeited (11,750) ​ 12.99 Outstanding at December 31, 2020 17,500 ​ $ 6.97 Exercisable at December 31, 2020 5,332 ​ $ 9.19 ​ There were 54,300 RSUs granted in 2020. The shares underlying the awards were assigned a weighted average value of $6.11 per share, which was the closing price of the Company’s common stock on the date of grants. These awards are scheduled to vest over three RSU activity during the year ended December 31, 2020 is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Shares Fair Value Unvested shares at January 1, 2020 — ​ — Granted 54,300 ​ $ 6.11 Vested — ​ — Forfeited or surrendered — ​ — Unvested shares at December 31, 2020 54,300 ​ 6.11 ​ In 2017, the Company’s board of directors had authorized the repurchase of 100,000 shares of common stock. A total of

LONG-TERM DEBT_2

LONG-TERM DEBT	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Long-Term Debt
LONG-TERM DEBT	7. Long-Term Debt Duluth Economic Development Authority Loan On April 1, 2016, the Company entered into a financing agreement (the “Financing Agreement”) under which the Duluth Economic Development Authority (the “Issuer”) agreed to sell $3,415,000 of its Tax Exempt Industrial Revenue Bonds, Series 2016 (IKONICS Project) (the “Bonds”) to Wells Fargo Bank, National Association (the “Bank”), and the Bank agreed to lend to the Company the proceeds received from the sale of the Bonds (the “Loan”). The closing of the sale of the Bonds occurred on April 29, 2016. The proceeds from the Loan were used to finance the construction of a 27,300-square foot building as well as related equipment for use in the Company’s manufacture of sound deadening technology used in the aerospace industry and products consisting of etched composites, ceramics, glass and silicon wafers, to be located in Duluth, Minnesota (the “Project”). The Loan required monthly payments of approximately $18,000, including interest. The Loans interest rate was 2.60% per year, subject to change based upon changes to the maximum federal corporate tax rate. Including debt costs of approximately $139,000, the Loan’s effective interest rate was 3.23%. During the first six months of 2021, the Company was informed that the bank will require the Company to repay the outstanding principal and any outstanding accrued and unpaid interest on April 1, 2021. On April 1, 2021, the Company repaid the entire loan including principal amount of $2.7 million and interest of $6,100 with existing cash on hand. When the loan was repaid, $82,000 of unamortized deferred financing costs were written off and charged to interest expense. Line of Credit The Company also has a bank line of credit providing for borrowings of up to $2,050,000 which expires on August 30, 2021 and bears interest at 1.8 percentage points over the 30-day LIBOR rate. The Company did not utilize this line of credit during the first six months of 2021 or 2020 and there were no borrowings outstanding as of June 30, 2021 or December 31, 2020. There are no financial covenants related to the line of credit, and the line of credit is collateralized by the Company’s assets.	7. LONG-TERM DEBT Duluth Economic Development Authority Loan On April 1, 2016, the Company entered into a financing agreement (the “Financing Agreement”) under which the Duluth Economic Development Authority (the “Issuer”) agreed to sell , including interest. The Loan bears interest at a rate of The Company is subject to certain customary covenants set forth in the associated covenant agreement, including a requirement that the Company maintain a debt service coverage ratio of not less than 1.25 to 1.00. The Loan is subject to mandatory purchase provisions, under which any owners of the Bonds (the “Owners”) may tender the Bonds to the Issuer on April 1, 2021, which would result in the Company repaying the outstanding loan principal and any outstanding accrued and unpaid interest to the Issuer at that time. If in the event the Bonds are not repurchased on April 1, 2021, the Bonds shall be subject to the interest rate and redemption provisions set forth in the associated covenant agreement. Subsequent to December 31, 2020 the Company was informed that the bank will recall the loan and require the Company to repay the outstanding principal and any outstanding accrued and unpaid interest on April 1, 2021. As of December 31, 2020, the Company reclassified the entire Loan from long-term debt to current liability. The remaining principal payments required under the agreement for years ended December 31, and the current and long-term portion of the principal, are as follows: ​ ​ ​ ​ ​ 2021 ​ 2,773,000 Less: Unamortized debt issuance costs ​ 85,000 Less: Current portion ​ 2,688,000 Long-term portion ​ $ — ​ In connection with the agreement, the Company incurred debt issuance costs of approximately $139,000 during 2016, which were deferred and are being amortized over the term of the Financing Agreement. Amortization of debt issuance costs was approximately $11,000 for 2020 and 2019 and is included in interest expense. Debt issuance costs of $85,000 are netted against long-term debt and current portion of long-term debt, respectively as of December 31, 2020 and 2019. The entire $85,000 of unamortized debt costs will be expensed when the loan is repaid in 2021. Paycheck Protection Program Loan On April 18, 2020, Company entered into a loan pursuant to the Paycheck Protection Program under the CARES Act, as administered by the U.S. Small Business Administration (the “SBA”). The loan, in the principal amount of $1,214,500 (the “PPP Loan”), was disbursed by BMO Harris Bank National Association (“Lender”) on April 22, 2020, pursuant to a Paycheck Protection Program Promissory Note and Agreement (the “Note and Agreement”). Under the CARES Act, loan forgiveness is available for the sum of documented payroll costs, covered rent payments, and covered utilities during an eight or twenty four-week period beginning on the approval date of the PPP Loan. For purposes of the CARES Act, payroll costs exclude compensation of an individual employee earning more than $100,000, prorated annually. Not more than 40% of the forgiven amount may be for non-payroll costs. Forgiveness is reduced if full-time headcount declines, or if salaries and wages for employees with salaries of $100,000 or less annually are reduced by more than 25%. During the fourth quarter of 2020, the Company submitted an application for 100% forgiveness of the PPP Loan. Prior to end of 2020, both the lender and the SBA forgave 100% of the Company’s PPP loan. The Company accounts for the PPP Loan as debt in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 470, Debt and accrues interest in accordance with the interest method under FASB ASC 835-30. When the loan was forgiven, the Company reduced the liability by the amount forgiven and recorded a gain on extinguishment in the statement of operations. Line of Credit The Company also has a bank line of credit providing for borrowings of up to $2,050,000 which expires on August 30, 2021 and bears interest at 1.8 percentage points over the 30-day LIBOR rate. The Company did not utilize this line of credit during 2020 or 2019 and there were no borrowings outstanding as of December 31, 2020 or 2019.There are no financial covenants related to the line of credit, and the Company expects that it will secure a similar line of credit when the current line of credit expires. Both the Duluth Development Authority Loan and the line of credit are collateralized by substantially all assets of the Company.

CHIEF EXECUTIVE OFFICER TRANSIT

CHIEF EXECUTIVE OFFICER TRANSITION	12 Months Ended
	Dec. 31, 2020
CHIEF EXECUTIVE OFFICER TRANSITION
CHIEF EXECUTIVE OFFICER TRANSITION	8. CHIEF EXECUTIVE OFFICER TRANSITION On January 7, 2020, Mr. Ulland formally announced his retirement as President and Chief Executive Officer of the Company, effective February 10, 2020. Mr. Ulland will continue to serve as Chairman of the Board. On January 7, 2020, the Company also announced that Glenn Sandgren has been appointed to the position of Chief Executive Officer effective February 10, 2020. Mr. Sandgren has also been appointed to the Board of Directors of the Company, also effective February 10, 2020. The Company incurred one-time costs of approximately $365,000 in 2020 related to the Chief Executive officer transition including severance payments, signing bonus, relocation expenses and executive search consulting expenses.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Cash Equivalents	Cash Equivalents States government agencies or instrumentalities, repurchase agreements fully collateralized by the United States Treasury, and United States government securities. The Company maintains its cash balances primarily in two financial institutions. As of December 31, 2020, the balance at both institutions exceeded the Federal Deposit Insurance Corporation coverage.
Short-Term Investments	Short-Term Investments
Inventories	Inventories The major components of inventories, net of inventory reserve, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Raw materials ​ $ 1,323,655 ​ $ 1,667,154 Work-in-progress ​ 428,753 ​ 419,906 Finished goods ​ 1,065,458 ​ 1,449,854 Reduction to LIFO cost ​ (1,172,891) ​ (1,356,378) ​ ​ ​ ​ ​ ​ ​ Total Inventories ​ $ 1,644,975 ​ $ 2,180,536 ​
Property, Plant and Equipment	Property, Plant and Equipment ​ ​ ​ ​ ​ Years Buildings ​ 15 – 40 Machinery and equipment 5 – 10 Office equipment 3 – 10 Vehicles ​ 3 ​
Patents	Patents —
Impairment of Long-lived Assets	Impairment of Long-lived Assets —
Fair Value of Financial Instruments	Fair Value of Financial Instruments
Revenue recognition	Revenue recognition certain customers. Revenue from all customers is recognized when a performance obligation is satisfied by transferring control of a distinct good or service to a customer. Individually promised goods and services in a contract are considered a distinct performance obligation and accounted for separately if the customer can benefit from the individual good or service on its own or with other resources that are readily available to the customer and the good or service is separately identifiable from other promises in the arrangement. When an arrangement includes multiple performance obligations, the consideration is allocated between the performance obligations in proportion to their estimated standalone selling price. Costs related to products delivered are recognized in the period incurred, unless criteria for capitalization of costs are met. Costs of revenues consist primarily of direct labor, manufacturing overhead, materials and components. The Company does not incur significant upfront costs to obtain a contract. If costs to obtain a contract were to become material, the costs would be recorded as an asset and amortized to expense in a manner consistent with the related recognition of revenue. The Company excludes from revenue governmental assessed and imposed taxes on revenue transactions that are invoiced to customers. The Company includes freight billed to customers in revenue. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold. The timing of revenue recognition, billings and cash collections results in accounts receivable on the balance sheet. Performance obligations The Company sells its products to both distributors and end-users. Each unit of product delivered under a customer order represents a distinct and separate performance obligation as the customer can benefit from each unit on its own or with other resources that are readily available to the customer and each unit of product is separately identifiable from other products in the arrangement. The transaction price for the Company’s products is the invoiced amount. The Company does not have variable consideration in the form of refunds, credits, rebates, price concessions, pricing incentives or other items impacting transaction price. The purchase order pricing in arrangements with customers is deemed to approximate standalone selling price; therefore, the Company does not need to allocate proceeds on a relative standalone selling price allocation between performance obligations. The Company does not disclose information about remaining performance obligations that have original expected durations of one year or less. There are no material obligations that extend beyond one year. Revenue is recognized when transfer of control occurs as defined by the terms in the customer agreement. The Company immediately recognizes incidental items that are immaterial in the context of the contract. The Company does not have any significant financing components in its customer arrangements as payment is received at or shortly after the point of sale, generally thirty to ninety days. The Company estimates returns based on an analysis of historical experience if the right to return products is granted to its customers. The Company does not record a return asset as non-conforming products are generally not returned. The Company’s return policy does not vary by geography. The customer has no rotation or price protection rights. Trade receivables. receivable balance for customers paying in a foreign currency. These balances are adjusted to each quarter or year-end spot rate. Foreign currency transactions and translation adjustments did not have a significant effect on the Balance Sheets, the Statements of Operations, Stockholders’ Equity or Cash Flows for 2020 and 2019. Sales commissions. Product warranties. International revenue.
Deferred Taxes	Deferred Taxes The Company follows the accounting standard on accounting for uncertainty in income taxes, which addresses the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the financial statements. Under this guidance, the Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement. The guidance on accounting for uncertainty in income taxes also addresses derecognition, classification, interest and penalties on income taxes, and accounting in interim periods.
Earnings Per Share (EPS)	Earnings Per Share (EPS) Shares used in the calculation of diluted EPS are summarized below: ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Weighted average common shares outstanding ​ 1,976,354 ​ 1,980,253 Dilutive effect of stock options and restricted stock units — ​ — Weighted average common and common equivalent shares outstanding 1,976,354 ​ 1,980,253 ​ If the Company was in a net income position at December 31, 2020, all 17,500 options outstanding with a weighted average exercise price of $6.97 would have remained excluded from the computation of weighted average common and common equivalent shares outstanding as the options were anti-dilutive. Restricted stock units of approximately 54,300 shares for the year-end December 31, 2020 would have remained excluded from the computation of weighted average common and common equivalent shares outstanding as they were anti-dilutive due to the amount of weighted-average unrecognized compensation related to these grants. At December 31, 2019, options to purchase 19,250 shares of common stock with a weighted average exercise price of $11.32 were outstanding, but were excluded from the computation of common share equivalents because they were anti-dilutive.
Employee Stock Plan	Employee Stock Plan —
Recent Accounting Pronouncements	Recent Accounting Pronouncements —
Use of Estimates	Use of Estimates

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Schedule of Inventory, Current	​ ​ ​ ​ ​ ​ ​ ​ ​ Jun 30, 2021 Dec 31, 2020 Raw materials ​ $ 1,286,151 ​ $ 1,323,655 Work-in-progress ​ 399,738 ​ 428,753 Finished goods ​ 1,140,543 ​ 1,065,458 Reduction to LIFO cost ​ (1,218,604) ​ (1,172,891) Total Inventories ​ $ 1,607,828 ​ $ 1,644,975	​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Raw materials ​ $ 1,323,655 ​ $ 1,667,154 Work-in-progress ​ 428,753 ​ 419,906 Finished goods ​ 1,065,458 ​ 1,449,854 Reduction to LIFO cost ​ (1,172,891) ​ (1,356,378) ​ ​ ​ ​ ​ ​ ​ Total Inventories ​ $ 1,644,975 ​ $ 2,180,536
Property, Plant and Equipment		​ ​ ​ ​ ​ Years Buildings ​ 15 – 40 Machinery and equipment 5 – 10 Office equipment 3 – 10 Vehicles ​ 3
Schedule of Weighted Average Number of Shares	​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Jun 30, 2021 Jun 30, 2020 Weighted average common shares outstanding ​ 1,977,959 1,976,354 Dilutive effect of stock options and restricted stock units ​ — — Weighted average common and common equivalent shares outstanding ​ 1,977,959 1,976,354 ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ Jun 30, 2021 Jun 30, 2020 Weighted average common shares outstanding 1,977,368 1,976,354 Dilutive effect of stock options and restricted stock units — — Weighted average common and common equivalent shares outstanding 1,977,368 1,976,354	​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Weighted average common shares outstanding ​ 1,976,354 ​ 1,980,253 Dilutive effect of stock options and restricted stock units — ​ — Weighted average common and common equivalent shares outstanding 1,976,354 ​ 1,980,253

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2020
Income Taxes
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Current: ​ ​ ​ ​ ​ ​ Federal ​ $ (216,000) ​ $ — State ​ ​ 6,000 ​ ​ 11,000 ​ ​ ​ (210,000) ​ ​ 11,000 Deferred — Federal ​ ​ — ​ ​ (183,000) ​ ​ $ (210,000) ​ $ (172,000)
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 Expected provision for federal income taxes ​ $ (136,000) ​ $ (207,000) State income taxes, net of federal benefit ​ (24,000) ​ (7,000) Permanent items ​ (249,000) ​ 11,000 Research and development credit ​ (23,000) ​ (29,000) Change in valuation allowance ​ 440,000 ​ 51,000 Change in tax law allowing NOL carryback claim ​ (217,000) ​ — Prior year true-ups and other ​ (1,000) ​ 9,000 ​ ​ $ (210,000) ​ $ (172,000)
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Deferred tax liabilities: ​ ​ ​ ​ ​ ​ Accrued vacation ​ $ 33,000 ​ $ 21,000 Inventories reserve ​ 17,000 ​ 42,000 Allowance for doubtful accounts ​ 2,000 ​ 3,000 Allowance for sales returns ​ 10,000 ​ 10,000 Research and development credit carryforward ​ 285,000 ​ 245,000 Accrued self-insured medical ​ — ​ 3,000 Property and equipment ​ (257,000) ​ (295,000) Patents ​ (50,000) ​ (53,000) Net operating loss ​ 411,000 ​ 230,000 Other ​ 17,000 ​ 8,000 Valuation allowance ​ (468,000) ​ (214,000) Net deferred tax liabilities ​ $ — ​ $ —

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2020
INTANGIBLE ASSETS
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	​ ​ ​ ​ ​ 2021 $ 25,000 2022 ​ 25,000 2023 ​ 25,000 2024 ​ 24,000 2025 ​ 24,000 Thereafter ​ 67,000
Schedule of Finite-Lived Intangible Assets [Table Text Block]	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ Gross ​ ​ ​ ​ Gross ​ ​ ​ ​ ​ Carrying ​ Accumulated ​ Carrying ​ Accumulated ​ Amount Amortization Amount Amortization Amortized intangible assets: ​ ​ ​ ​ Patents ​ $ 450,982 ​ $ (207,399) ​ $ 452,978 ​ $ (181,609) ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Aggregate amortization expense: ​ ​ ​ ​ ​ ​ For the years ended December 31 ​ $ 25,790 ​ $ 31,869

SEGMENT INFORMATION (Tables)_2

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Information
Schedule of Segment Reporting Information, by Segment [Table Text Block]	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline ​ Imaging ​ DTX ​ AMS ​ Unalloc. ​ Total Net sales ​ $ 8,475,743 ​ $ 3,709,318 ​ $ 294,929 ​ $ 952,230 $ — ​ $ 13,432,220 Cost of goods sold ​ 6,222,902 ​ 1,972,076 ​ 140,866 ​ 1,191,299 ​ — ​ 9,527,143 Gross profit (loss) ​ 2,252,841 ​ 1,737,242 ​ 154,063 ​ (239,069) ​ — ​ 3,905,077 Selling, general, and administrative* ​ 1,297,045 ​ 880,404 ​ 125,752 ​ 275,147 ​ 2,441,256 ​ 5,019,604 Research and development* ​ — ​ — ​ — ​ — ​ 671,493 ​ 671,493 Income (loss) from operations ​ $ 955,796 ​ $ 856,838 ​ $ 28,311 ​ $ (514,216) ​ $ (3,112,749) ​ $ (1,786,020) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ IKONICS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Chromaline Imaging DTX AMS Unalloc. Total Net sales ​ $ 11,472,111 ​ $ 4,191,175 ​ $ 393,804 ​ $ 1,561,469 ​ $ — ​ $ 17,618,559 Cost of goods sold ​ 8,389,404 ​ 2,273,641 ​ 157,650 ​ 1,400,675 ​ — ​ 12,221,370 Gross profit ​ 3,082,707 ​ 1,917,534 ​ 236,154 ​ 160,794 ​ — ​ 5,397,189 Selling, general, and administrative* ​ 1,832,473 ​ 1,081,847 ​ 149,924 ​ 361,342 ​ 2,058,000 ​ 5,483,586 Research and development* ​ — ​ — ​ — ​ — ​ 870,279 ​ 870,279 Income (loss) from operations ​ $ 1,250,234 ​ $ 835,687 ​ $ 86,230 ​ $ (200,548) ​ $ (2,928,279) ​ $ (956,676) ​ ​ ​ ​ ​ ​ ​ ​ ​ Dec 31, 2020 Dec 31, 2019 Chromaline ​ $ 1,676,592 ​ $ 1,916,066 IKONICS Imaging ​ 396,116 ​ 304,791 DTX ​ 35,983 ​ 13,919 AMS ​ 57,676 ​ 252,363 Unallocated ​ (47,154) ​ (52,421) ​ ​ ​ ​ ​ ​ ​ Total ​ $ 2,119,213 ​ $ 2,434,718

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Stock-Based Compensation
Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]	RSU activity during the six months ended June 30, 2021 is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ Shares ​ Fair Value Unvested shares at January 1, 2021 54,300 ​ $ 6.11 Granted 36,550 ​ 11.01 Vested (1,340) ​ 11.30 Forfeited or surrendered (2,400) ​ 6.11 Unvested shares at June 30, 2021 87,110 ​ 8.09	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Shares Fair Value Unvested shares at January 1, 2020 — ​ — Granted 54,300 ​ $ 6.11 Vested — ​ — Forfeited or surrendered — ​ — Unvested shares at December 31, 2020 54,300 ​ 6.11
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Stock option activity during the six months ended June 30, 2021 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2021 17,500 ​ $ 6.97 Granted 10,000 ​ 11.50 Exercised (3,000) ​ 9.23 Expired and forfeited (1,000) ​ 10.75 Outstanding at June 30, 2021 23,500 ​ $ 8.45 Exercisable at June 30, 2021 5,165 ​ $ 6.54	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ ​ Shares ​ Price Outstanding at January 1, 2020 19,250 ​ $ 11.32 Granted 10,000 ​ 5.67 Exercised — ​ — Expired and forfeited (11,750) ​ 12.99 Outstanding at December 31, 2020 17,500 ​ $ 6.97 Exercisable at December 31, 2020 5,332 ​ $ 9.19
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 2020 Dividend yield ​ — ​ — ​ Expected volatility ​ 51.6 % ​ 40.3 % Expected life of option (years) ​ 10 ​ 10 ​ Risk-free interest rate ​ 0.5 % ​ 1.4 % Fair value of each option on grant date ​ $ 6.84 ​ $ 2.90 ​	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Dividend yield ​ 0 ​ 0 ​ Expected volatility ​ 40.3 % ​ 37.5 % Expected life of option (years) ​ 10 ​ 5 ​ Risk-free interest rate ​ 1.4 % ​ 1.7 % Fair value of each option on grant date ​ $ 2.90 ​ $ 2.53 ​

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2020
Long-Term Debt
Schedule of Maturities of Long-term Debt [Table Text Block]	​ ​ ​ ​ ​ 2021 ​ 2,773,000 Less: Unamortized debt issuance costs ​ 85,000 Less: Current portion ​ 2,688,000 Long-term portion ​ $ —

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2021USD ($)shares	Jun. 30, 2021USD ($)shares	Dec. 31, 2020USD ($)customer$ / sharesshares	Dec. 31, 2019USD ($)customer$ / sharesshares
Long-term Debt, Current Maturities, Total	$ 0	$ 0	$ 2,688,396	$ 133,287
Short-term Investments, Total			0	2,205,000
FIFO Inventory Amount			1,173,000	1,356,000
Inventory Write-down			116,000	0
Inventory Valuation Reserves, Ending Balance			$ 13,000	$ 12,000
Finite-Lived Intangible Asset, Useful Life (Year)			8 years 6 months
Impairment of Long-Lived Assets Held-for-use			$ 0
Number of Option Shares Excluded from Weighted Average Common Shares Outstanding (in shares) | shares			17,500	19,250
Weighted Average Exercise Price Options Excluded From Weighted Average Common Share Outstanding (in dollars per share) | $ / shares			$ 6.97	$ 11.32
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares	87,110	87,110	54,300
Export [Member] | Minimum [Member]
Accounts Receivable Credit Term (Day)			30 days
Export [Member] | Maximum [Member]
Accounts Receivable Credit Term (Day)			90 days
Revenue, Segment Benchmark [Member] | Customer Concentration Risk [Member] | Export [Member]
Concentration Risk, Percentage			29.70%	29.40%
Revenue Benchmark [Member] | Customer Concentration Risk [Member]
Number of Major Customers | customer			0	0
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | Geographic Distribution, Foreign [Member]
Concentration Risk, Percentage			29.70%	29.40%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Major Components of Inventories (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Raw materials	$ 1,286,151	$ 1,323,655	$ 1,667,154
Work-in-progress	399,738	428,753	419,906
Finished goods	1,140,543	1,065,458	1,449,854
Reduction to LIFO cost	(1,218,604)	(1,172,891)	(1,356,378)
Total Inventories	$ 1,607,828	$ 1,644,975	$ 2,180,536

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Property, Plant and Equipment, Estimate Useful Lives (Details)	12 Months Ended
	Dec. 31, 2020
Building [Member] | Minimum [Member]
Estimated useful lives (Year)	15 years
Building [Member] | Maximum [Member]
Estimated useful lives (Year)	40 years
Machinery and Equipment [Member] | Minimum [Member]
Estimated useful lives (Year)	5 years
Machinery and Equipment [Member] | Maximum [Member]
Estimated useful lives (Year)	10 years
Office Equipment [Member] | Minimum [Member]
Estimated useful lives (Year)	3 years
Office Equipment [Member] | Maximum [Member]
Estimated useful lives (Year)	10 years
Vehicles [Member]
Estimated useful lives (Year)	3 years

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Calculation of Diluted EPS (Details) - shares	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Weighted average common shares outstanding (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253
Dilutive effect of stock options and restricted stock units (in shares)	0	0	0	0
Weighted average common and common equivalent shares outstanding (in shares)	1,977,959	1,976,354	1,977,368	1,976,354	1,976,354	1,980,253

INCOME TAXES (Details)_2

INCOME TAXES (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Jun. 30, 2021
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Unrecognized Tax Benefits, Ending Balance	$ 0	$ 0
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	1,847,000
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	104,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	468,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	$ 214,000

INCOME TAXES - Income Tax Expen

INCOME TAXES - Income Tax Expense (Benefit) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Current:
Federal					$ (216,000)
State					6,000	$ 11,000
Current Income Tax Expense (Benefit), Total					(210,000)	11,000
Deferred - Federal						(183,000)
Income Tax Expense (Benefit), Total	$ 823	$ 0	$ (19,524)	$ (238,929)	$ (210,000)	$ (172,000)

INCOME TAXES - Income Taxes Rec

INCOME TAXES - Income Taxes Reconciliation (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Income Taxes
Expected provision for federal income taxes					$ (136,000)	$ (207,000)
State income taxes, net of federal benefit					(24,000)	(7,000)
Permanent items					(249,000)	11,000
Research and development credit					(23,000)	(29,000)
Change in valuation allowance					440,000	51,000
Change in tax law allowing NOL carryback claim					(217,000)
Prior year true-ups and other					(1,000)	9,000
Income Tax Expense (Benefit), Total	$ 823	$ 0	$ (19,524)	$ (238,929)	$ (210,000)	$ (172,000)

INCOME TAXES - Net Deferred Tax

INCOME TAXES - Net Deferred Tax Liabilities (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities:
Accrued vacation	$ 33,000	$ 21,000
Inventories reserve	17,000	42,000
Allowance for doubtful accounts	2,000	3,000
Allowance for sales returns	10,000	10,000
Research and development credit carryforward	285,000	245,000
Accrued self-insured medical		3,000
Property and equipment	(257,000)	(295,000)
Patents	(50,000)	(53,000)
Net operating loss	411,000	230,000
Other	17,000	8,000
Valuation allowance	(468,000)	(214,000)
Net deferred tax liabilities

INTANGIBLE ASSETS (Details)

INTANGIBLE ASSETS (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Impairment of Intangible Assets, Finite-lived	$ 0	$ 16,906	$ 16,906	$ 92,833
Licensing Agreements [Member]
Royalty Expense			$ 8,000	$ 10,000
Licensing Agreements [Member] | Minimum [Member]
Payment of Royalty in Percentage			3.00%
Licensing Agreements [Member] | Maximum [Member]
Payment of Royalty in Percentage			5.00%

INTANGIBLE ASSETS - Summary of

INTANGIBLE ASSETS - Summary of Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2021
Accumulated amortization	$ (207,399)	$ (181,609)	$ (205,697)
Aggregate amortization expense	25,790	31,869
Patents [Member]
Gross carrying amount	450,982	452,978
Accumulated amortization	$ (207,399)	$ (181,609)

INTANGIBLE ASSETS - Estimated A

INTANGIBLE ASSETS - Estimated Amortization Expense (Details)	Dec. 31, 2020USD ($)
INTANGIBLE ASSETS
2021	$ 25,000
2022	25,000
2023	25,000
2024	24,000
2025	24,000
Thereafter	$ 67,000

RETIREMENT PLAN (Details)

RETIREMENT PLAN (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
RETIREMENT PLAN
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent		5.00%
Defined Contribution Plan, Cost	$ 120,000	$ 241,000

SEGMENT INFORMATION (Details)_2

SEGMENT INFORMATION (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2021segment	Dec. 31, 2020
Segment Information
Number of Reportable Segments	4	4

SEGMENT INFORMATION - Reporta_2

SEGMENT INFORMATION - Reportable Segments (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Net sales	$ 4,251,348	$ 2,572,439	$ 7,324,756	$ 6,069,631	$ 13,432,220	$ 17,618,559
Cost of goods sold	2,822,044	2,187,544	4,899,120	4,531,504	9,527,143	12,221,370
Gross profit	1,429,304	384,895	2,425,636	1,538,127	3,905,077	5,397,189
Selling, general, and administrative*	1,944,502	1,202,307	3,128,093	2,983,327	5,019,604	5,483,586
Research and development*	128,895	201,234	263,817	384,814	671,493	870,279
Income (loss) from operations	(644,093)	(1,018,646)	(966,274)	(1,830,014)	(1,786,020)	(956,676)
Trade receivables	1,651,035		1,651,035		2,119,213	2,434,718
Operating Segments [Member]
Trade receivables	1,651,035		1,651,035		2,119,213
Segment Reconciling Items [Member]
Net sales
Cost of goods sold
Gross profit
Selling, general, and administrative*	1,304,485	524,504	1,924,878	1,462,961	2,441,256	2,058,000
Research and development*	128,895	201,234	263,817	384,814	671,493	870,279
Income (loss) from operations	(1,433,380)	(725,738)	(2,188,695)	(1,847,775)	(3,112,749)	(2,928,279)
Trade receivables	(37,979)		(37,979)		(47,154)	(52,421)
Chromaline [Member]
Net sales	2,653,733	1,619,986	4,352,414	3,584,326
Cost of goods sold	1,905,738	1,407,362	3,140,523	2,825,631
Gross profit	747,995	212,624	1,211,891	758,695
Selling, general, and administrative*	289,928	366,136	547,930	792,355
Income (loss) from operations	458,067	(153,512)	663,961	(33,660)
Chromaline [Member] | Operating Segments [Member]
Net sales					8,475,743	11,472,111
Cost of goods sold					6,222,902	8,389,404
Gross profit					2,252,841	3,082,707
Selling, general, and administrative*					1,297,045	1,832,473
Research and development*
Income (loss) from operations					955,796	1,250,234
Trade receivables	1,150,630		1,150,630		1,676,592	1,916,066
Ikonics Imaging [Member]
Net sales	1,264,855	625,800	2,351,456	1,595,899
Cost of goods sold	644,071	419,985	1,193,726	897,708
Gross profit	620,784	205,815	1,157,730	698,191
Selling, general, and administrative*	259,219	224,573	475,755	503,435
Income (loss) from operations	361,565	(18,758)	681,975	194,756
Ikonics Imaging [Member] | Operating Segments [Member]
Net sales					3,709,318	4,191,175
Cost of goods sold					1,972,076	2,273,641
Gross profit					1,737,242	1,917,534
Selling, general, and administrative*					880,404	1,081,847
Research and development*
Income (loss) from operations					856,838	835,687
Trade receivables	356,216		356,216		396,116	304,791
DTX [Member]
Net sales	85,444	49,053	161,755	161,582
Cost of goods sold	34,260	24,346	77,052	76,092
Gross profit	51,184	24,707	84,703	85,490
Selling, general, and administrative*	32,001	30,059	62,040	64,432
Income (loss) from operations	19,183	(5,352)	22,663	21,058
DTX [Member] | Operating Segments [Member]
Net sales					294,929	393,804
Cost of goods sold					140,866	157,650
Gross profit					154,063	236,154
Selling, general, and administrative*					125,752	149,924
Research and development*
Income (loss) from operations					28,311	86,230
Trade receivables	26,759		26,759		35,983	13,919
AMS [Member]
Net sales	247,316	277,600	459,131	727,824
Cost of goods sold	237,975	335,851	487,819	732,073
Gross profit	9,341	(58,251)	(28,688)	(4,249)
Selling, general, and administrative*	58,869	57,035	117,490	160,144
Income (loss) from operations	(49,528)	$ (115,286)	(146,178)	$ (164,393)
AMS [Member] | Operating Segments [Member]
Net sales					952,230	1,561,469
Cost of goods sold					1,191,299	1,400,675
Gross profit					(239,069)	160,794
Selling, general, and administrative*					275,147	361,342
Research and development*
Income (loss) from operations					(514,216)	(200,548)
Trade receivables	$ 155,409		$ 155,409		$ 57,676	$ 252,363

STOCKHOLDERS' EQUITY (Details)

STOCKHOLDERS' EQUITY (Details) - USD ($)	6 Months Ended		12 Months Ended			48 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2020	Apr. 29, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)	23,500		17,500	19,250		17,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	10,000	10,000	10,000	3,250
Share-based Payment Arrangement, Expense	$ 131,600	$ 7,400	$ 22,000	$ 9,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 674,000		$ 348,000			$ 348,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	4 years		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)	3,000	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	4 years
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)					100,000		100,000
Stock Repurchased During Period, Shares (in shares)			0	7,199	33,500	40,699
Stock Repurchase Program, Number of Additional Shares Authorized to be Repurchased (in shares)							33,500
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares)			92,801			92,801
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	36,550	0	54,300	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 11.01		$ 6.11
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			3 years
The 1995 Incentive Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)			442,750			442,750
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)	1,000		5,000			5,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)	102,157
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period (in shares)			11,750
The 1995 Incentive Stock Option Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)				102,157
The 1995 Incentive Stock Option Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	442,750
The 2019 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)	3,957		47,107			47,107
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period (in shares)	12,750		750
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	23,250		13,250
The 2019 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period (in shares)	102,157
The 2019 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			54,300
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	90,850

STOCKHOLDERS' EQUITY - Assumpti

STOCKHOLDERS' EQUITY - Assumptions (Details) - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Expected volatility	51.60%	40.30%
Expected life of option (years) (Year)	10 years	10 years
Risk-free interest rate	0.50%	1.40%
Fair value of each option on grant date (in dollars per share)	$ 6.84	$ 2.90
Share-based Payment Arrangement, Option [Member]
Dividend yield			0.00%	0.00%
Expected volatility			40.30%	37.50%
Expected life of option (years) (Year)			10 years	5 years
Risk-free interest rate			1.40%	1.70%
Fair value of each option on grant date (in dollars per share)			$ 2.90	$ 2.53

STOCKHOLDERS' EQUITY - Stock Op

STOCKHOLDERS' EQUITY - Stock Option Activity (Details) - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Stock-Based Compensation
Outstanding, Shares (in shares)	17,500	19,250	19,250
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.97	$ 11.32	$ 11.32
Granted, Shares (in shares)	10,000	10,000	10,000	3,250
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 11.50		$ 5.67
Exercise of stock options (in shares)	3,000	0	0	0
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 9.23
Expired and forfeited, Shares (in shares)	(1,000)		(11,750)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 10.75		$ 12.99
Outstanding, Shares (in shares)	23,500		17,500	19,250
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 8.45		$ 6.97	$ 11.32
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	5,165		5,332
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 6.54		$ 9.19

STOCKHOLDERS' EQUITY - Restrict

STOCKHOLDERS' EQUITY - Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Unvested, shares (in shares)	54,300
Unvested, weighted average grant date fair value (in dollars per share)	$ 6.11
Granted, shares (in shares)	36,550	0	54,300	0
Granted, weighted average grant date fair value (in dollars per share)	$ 11.01		$ 6.11
Vested, shares (in shares)	(1,340)
Vested, weighted average grant date fair value (in dollars per share)	$ 11.30
Forfeited or surrendered, shares (in shares)	(2,400)
Forfeited or surrendered, weighted average grant date fair value (in dollars per share)	$ 6.11
Unvested, shares (in shares)	87,110		54,300
Unvested, weighted average grant date fair value (in dollars per share)	$ 8.09		$ 6.11

LONG-TERM DEBT (Details)_2

LONG-TERM DEBT (Details)	Apr. 18, 2020USD ($)	Apr. 29, 2016USD ($)ft²	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Apr. 01, 2016USD ($)
Duluth Economic Development Authority bonds sold to bank to finance capital expenditures							$ 3,415,000
Proceeds from Issuance of Long-term Debt, Total			$ 0	$ 1,214,500	$ 1,214,500
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate			1.80%
Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 2,050,000		2,050,000
Long-term Line of Credit, Total			$ 0		$ 0	$ 0
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate					1.80%
Loan [Member]
Debt Instrument, Periodic Payment, Total		$ 18,000
Debt Instrument, Interest Rate, Stated Percentage		2.60%
Debt Issuance Costs, Gross		$ 139,000
Debt Instrument, Interest Rate, Effective Percentage			3.23%		3.23%
Debt Service Coverage Ratio		1.25
Amortization of Debt Issuance Costs					$ 11,000	11,000
Debt Issuance Costs, Noncurrent, Net, Total					85,000	$ 85,000
Amortization of Debt Issuance Costs Annual Expected Amount Over Remainder of Debt Term					$ 85,000
Loan [Member] | Building [Member]
Area of Real Estate Property (Square Foot) | ft²		27,300
SBA CARES Act Paycheck Protection Program [Member]
Proceeds from Issuance of Long-term Debt, Total	$ 1,214,500
Duluth Economic Development Authority [Member]
Duluth Economic Development Authority bonds sold to bank to finance capital expenditures							$ 3,415,000

LONG-TERM DEBT - Remaining Prin

LONG-TERM DEBT - Remaining Principal Payments and the Current and Long-term Portion of Principal (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Long-Term Debt
2021		$ 2,773,000
Less: Unamortized debt issuance costs		85,000
Current portion of long-term debt	$ 0	2,688,396	$ 133,287
Long-term portion			$ 2,688,357

Chief Executive Officer Trans_2

Chief Executive Officer Transition (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
CHIEF EXECUTIVE OFFICER TRANSITION
Officer Transition Expense	$ 365,000