| Document and Entity Information | 6 Months Ended |
| Jun. 30, 2021 | |
| Cover Abstract | |
| Entity Registrant Name | ALLOT LTD. |
| Entity Central Index Key | 0001365767 |
| Document Type | 6-K |
| Document Period End Date | Jun. 30, 2021 |
| Amendment Flag | false |
| Document Fiscal Year Focus | 2021 |
| Current Fiscal Year End Date | --12-31 |
| Document Fiscal Period Focus | Q2 |
| Entity Address, Address Line One | 22 Hanagar Street |
| Entity Address, Address Line Two | Neve Ne'eman Industrial Zone B |
| Entity Address, City or Town | Hod-Hasharon |
| Entity Address, Postal Zip Code | 45240 |
| Entity Address, Country | IL |
| CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands | Jun. 30, 2021 | Dec. 31, 2020 |
| CURRENT ASSETS: | ||
| Cash and cash equivalents | $ 10,606 | $ 23,599 |
| Short-term bank deposits | 71,425 | 47,225 |
| Restricted deposits | 4,074 | 1,200 |
| Available-for-sale marketable securities | 19,308 | 27,178 |
| Trade receivables, net | 30,941 | 20,685 |
| Other receivables and prepaid expenses | 8,862 | 14,205 |
| Inventories | 9,297 | 12,586 |
| Total current assets | 154,513 | 146,678 |
| LONG-TERM ASSETS: | ||
| Long-term bank deposits | 215 | 215 |
| Severance pay fund | 469 | 434 |
| Operating lease right-of-use assets | 2,974 | 4,458 |
| Deferred taxes | 246 | 420 |
| Other assets | 1,603 | 2,975 |
| Total long-term assets | 5,507 | 8,502 |
| PROPERTY AND EQUIPMENT, NET | 13,394 | 11,993 |
| GOODWILL AND INTANGIBLE ASSETS, NET | 35,608 | 34,427 |
| Total assets | 209,022 | 201,600 |
| CURRENT LIABILITIES: | ||
| Trade payables | 1,556 | 2,092 |
| Deferred revenues | 32,852 | 26,658 |
| Short-term operating lease liabilities | 1,573 | 2,813 |
| Other payables and accrued expenses | 23,569 | 27,299 |
| Total current liabilities | 59,550 | 58,862 |
| LONG-TERM LIABILITIES: | ||
| Deferred revenues | 20,200 | 9,782 |
| Long-term operating lease liabilities | 880 | 1,835 |
| Accrued severance pay | 944 | 969 |
| Total long-term liabilities | 22,024 | 12,586 |
| SHAREHOLDERS' EQUITY | 127,448 | 130,152 |
| Total liabilities and shareholders' equity | $ 209,022 | $ 201,600 |
| CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
| Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | |
| Income Statement [Abstract] | ||||
| Revenues | $ 35,288 | $ 32,790 | $ 66,471 | $ 62,079 |
| Cost of revenues | 10,822 | 9,838 | 20,413 | 17,448 |
| Gross profit | 24,466 | 22,952 | 46,058 | 44,631 |
| Operating expenses: | ||||
| Research and development costs, net | 11,373 | 10,396 | 21,940 | 19,095 |
| Sales and marketing | 12,818 | 11,780 | 24,411 | 23,302 |
| General and administrative | 4,080 | 4,554 | 7,280 | 7,595 |
| Total operating expenses | 28,271 | 26,730 | 53,631 | 49,992 |
| Operating loss | (3,805) | (3,778) | (7,573) | (5,361) |
| Financial and other income, net | 194 | 717 | 309 | 868 |
| Loss before income tax expenses | (3,611) | (3,061) | (7,264) | (4,493) |
| Tax expenses | 368 | 553 | 673 | 781 |
| Net Loss | $ (3,979) | $ (3,614) | $ (7,937) | $ (5,274) |
| Basic net loss per share (in dollars per share) | $ (0.11) | $ (0.10) | $ (0.22) | $ (0.15) |
| Diluted net loss per share (in dollars per share) | $ (0.11) | $ (0.10) | $ (0.22) | $ (0.15) |
| CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - 6 months ended Jun. 30, 2021 $ in Thousands | USD ($) |
| Balance at Dec. 31, 2020 | $ 130,152 |
| Net loss | (7,937) |
| Balance at Jun. 30, 2021 | $ 127,448 |
| CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
| Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | |
| Cash flows from operating activities: | ||||
| Net loss | $ (3,979) | $ (3,614) | $ (7,937) | $ (5,274) |
| Adjustments to reconcile net income to net cash provided by (used in) operating activities: | ||||
| Depreciation | 1,141 | 897 | 2,229 | 1,685 |
| Stock-based compensation | 2,261 | 1,232 | 3,705 | 2,156 |
| Amortization of intangible assets | 234 | 152 | 471 | 304 |
| Increase (decrease) in accrued severance pay, net | 12 | (1) | (60) | 0 |
| Decrease (increase) in other assets | (458) | (1) | 1,041 | 159 |
| Decrease in accrued interest and amortization of premium on marketable securities | 32 | 57 | 107 | 228 |
| Changes in operating leases, net | (479) | 544 | (711) | (167) |
| Decrease (increase) in trade receivables | (3,113) | 1,616 | (10,256) | 7,484 |
| Decrease (Increase) in other receivables and prepaid expenses | 3,094 | (518) | 3,522 | (919) |
| Decrease (Increase) in inventories | 4,246 | (2,113) | 3,289 | (6,598) |
| Decrease in long-term deferred taxes, net | 103 | 20 | 175 | 104 |
| Increase (Decrease) in trade payables | 334 | (6,468) | (536) | (4,200) |
| Increase (decrease) in employees and payroll accruals | 1,286 | 1,024 | (623) | (301) |
| Increase (decrease) in deferred revenues | 1,640 | 4,169 | 16,612 | (1,457) |
| Increase (Decrease) in other payables, accrued expenses and other long term liabilities | (2,761) | 2,235 | (3,364) | 517 |
| Net cash provided by (used in) operating activities | 3,593 | (769) | 7,664 | (6,279) |
| Cash flows from investing activities: | ||||
| Decrease (increase) in restricted deposit | (2,440) | 9,002 | (2,874) | 10,502 |
| Redemption of (Investment in) short-term deposits | 100 | (14,200) | (24,200) | (9,443) |
| Purchase of property and equipment | (1,934) | (2,345) | (3,629) | (3,696) |
| Investment in available-for sale marketable securities | 0 | 0 | 0 | (375) |
| Proceeds from sales and maturity of available-for sale marketable securities | 3,231 | 8,523 | 7,579 | 21,446 |
| Net cash provided by (used in) investing activities | (1,043) | 980 | (23,124) | 18,434 |
| Cash flows from financing activities: | ||||
| Proceeds from exercise of stock options | 908 | 837 | 2,467 | 1,457 |
| Net cash provided by financing activities | 908 | 837 | 2,467 | 1,457 |
| Increase (Decrease) in cash and cash equivalents | 3,458 | 1,048 | (12,993) | 13,612 |
| Cash and cash equivalents at the beginning of the period | 7,148 | 29,494 | 23,599 | 16,930 |
| Cash and cash equivalents at the end of the period | $ 10,606 | $ 30,542 | $ 10,606 | $ 30,542 |
