Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands | Common Stock [Member] | Additional Paid-in Capital [Member] | Warrant [Member] | Retained Earnings [Member] | Treasury Stock [Member] | Total Acorn Energy, Inc. Shareholders' Deficit [Member] | Noncontrolling Interest [Member] | Total |
Beginning balance, value at Dec. 31, 2019 | $ 396 | $ 101,655 | $ 1,021 | $ (100,682) | $ (3,036) | $ (646) | $ 1 | $ (645) |
Beginning balance, shares at Dec. 31, 2019 | 39,591 | | | | 802 | | | |
Net loss | | | | (283) | | (283) | (1) | (284) |
Accrued dividend in OmniMetrix preferred shares | | | | | | | (1) | (1) |
Proceeds from stock option exercise | $ 1 | 18 | | | | 19 | | 19 |
Proceeds from stock option exercise, shares | 96 | | | | | | | |
Stock option compensation | | 6 | | | | 6 | | 6 |
Ending balance, value at Mar. 31, 2020 | $ 397 | 101,679 | 1,021 | (100,965) | $ (3,036) | (904) | (1) | (905) |
Ending balance, shares at Mar. 31, 2020 | 39,687 | | | | 802 | | | |
Beginning balance, value at Dec. 31, 2019 | $ 396 | 101,655 | 1,021 | (100,682) | $ (3,036) | (646) | 1 | (645) |
Beginning balance, shares at Dec. 31, 2019 | 39,591 | | | | 802 | | | |
Net loss | | | | | | | | (347) |
Ending balance, value at Sep. 30, 2020 | $ 397 | 102,718 | 3 | (101,030) | $ (3,036) | (948) | (1) | (949) |
Ending balance, shares at Sep. 30, 2020 | 39,687 | | | | 802 | | | |
Beginning balance, value at Mar. 31, 2020 | $ 397 | 101,679 | 1,021 | (100,965) | $ (3,036) | (904) | (1) | (905) |
Beginning balance, shares at Mar. 31, 2020 | 39,687 | | | | 802 | | | |
Net loss | | | | (33) | | (33) | 1 | (32) |
Accrued dividend in OmniMetrix preferred shares | | | | | | | (1) | (1) |
Value of expired warrants | | 1,018 | (1,018) | | | | | |
Stock option compensation | | 13 | | | | 13 | | 13 |
Ending balance, value at Jun. 30, 2020 | $ 397 | 102,710 | 3 | (100,998) | $ (3,036) | (924) | (1) | (925) |
Ending balance, shares at Jun. 30, 2020 | 39,687 | | | | 802 | | | |
Net loss | | | | (32) | | (32) | 1 | (31) |
Accrued dividend in OmniMetrix preferred shares | | | | | | | (1) | (1) |
Stock option compensation | | 8 | | | | 8 | | 8 |
Ending balance, value at Sep. 30, 2020 | $ 397 | 102,718 | 3 | (101,030) | $ (3,036) | (948) | (1) | (949) |
Ending balance, shares at Sep. 30, 2020 | 39,687 | | | | 802 | | | |
Beginning balance, value at Dec. 31, 2020 | $ 397 | 102,726 | 3 | (100,613) | $ (3,036) | (523) | 4 | (519) |
Beginning balance, shares at Dec. 31, 2020 | 39,687 | | | | 802 | | | |
Net loss | | | | 20 | | 20 | 2 | 22 |
Accrued dividend in OmniMetrix preferred shares | | | | | | | (1) | (1) |
Proceeds from stock option exercise, shares | 96 | | | | | | | |
Stock option compensation | | 15 | | | | 15 | | 15 |
Ending balance, value at Mar. 31, 2021 | $ 397 | 102,741 | 3 | (100,593) | $ (3,036) | (488) | 5 | (483) |
Ending balance, shares at Mar. 31, 2021 | 39,687 | | | | 802 | | | |
Beginning balance, value at Dec. 31, 2020 | $ 397 | 102,726 | 3 | (100,613) | $ (3,036) | (523) | 4 | (519) |
Beginning balance, shares at Dec. 31, 2020 | 39,687 | | | | 802 | | | |
Net loss | | | | | | | | $ 51 |
Proceeds from stock option exercise, shares | | | | | | | | |
Ending balance, value at Sep. 30, 2021 | $ 397 | 102,784 | 3 | (100,568) | $ (3,036) | (420) | 7 | $ (413) |
Ending balance, shares at Sep. 30, 2021 | 39,687 | | | | 802 | | | |
Beginning balance, value at Mar. 31, 2021 | $ 397 | 102,741 | 3 | (100,593) | $ (3,036) | (488) | 5 | (483) |
Beginning balance, shares at Mar. 31, 2021 | 39,687 | | | | 802 | | | |
Net loss | | | | 2 | | 2 | 2 | 4 |
Accrued dividend in OmniMetrix preferred shares | | | | | | | (1) | (1) |
Stock option compensation | | 21 | | | | 21 | | 21 |
Ending balance, value at Jun. 30, 2021 | $ 397 | 102,762 | 3 | (100,591) | $ (3,036) | (465) | 6 | (459) |
Ending balance, shares at Jun. 30, 2021 | 39,687 | | | | 802 | | | |
Net loss | | | | 23 | | 23 | 2 | 25 |
Accrued dividend in OmniMetrix preferred shares | | | | | | | (1) | (1) |
Stock option compensation | | 22 | | | | 22 | | 22 |
Ending balance, value at Sep. 30, 2021 | $ 397 | $ 102,784 | $ 3 | $ (100,568) | $ (3,036) | $ (420) | $ 7 | $ (413) |
Ending balance, shares at Sep. 30, 2021 | 39,687 | | | | 802 | | | |