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ACCOUNTING POLICIES (Details Textual) - USD ($) $ / shares in Units, shares in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Jan. 01, 2019
Accounting Policies [Line Items] |  |  |  |
Advertising expense | $ 144,000 | $ 113,000 | $ 140,000 |
Interest costs capitalized | 110,000 | 115,000 | 138,000 |
Original cost of operating lease contracts | 92,135,000 | 94,031,000 |  |
Accumulated depreciation | 55,148,000 | 53,716,000 |  |
Insurance coverage receivable | 0 | 1,137,000 |  |
Revenue recognized, including assessed tax | 19,396,000 |  |  |
Revenue recognized, excluding assessed tax | $ 20,605,000 | $ 19,714,000 | $ 19,556,000 |
Percentage of tax benefit realized upon settlement | 50.00% |  |  |
Asset retirement obligation liability | $ 0 |  |  |
Antidilutive securities excluded from computation of earnings per share (in shares) | 387 | 519 | 14 |
Operating lease, liability | $ 1,106,000 |  |  |
Operating lease, right-of-use asset | 1,106,000 |  |  |
Mevion Medical Systems Inc |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Gain on business interruption insurance recovery | $ 185,000 |  |  |
Medical Services Revenues |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Concentration risk, percentage | 100.00% | 100.00% | 100.00% |
Customer One | Medical Services Revenues |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Concentration risk, percentage | 30.00% | 26.00% | 21.00% |
Restricted Stock Units (RSUs) |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Antidilutive securities excluded from computation of earnings per share (in shares) | 3 | 4 | 4 |
Accounting Standards Update 2014-09 |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Revenue recognized, excluding assessed tax | $ 1,209,000 |  |  |
Accounting Standards Update 2016-02 |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Operating lease, liability |  |  |  | $ 1,362,000
Operating lease, right-of-use asset |  |  |  | $ 1,362,000
PBRT |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Property equipment, useful life | 20 years |  |  |
Mevion Medical Systems Inc |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Cost of repairs | $ 977,000 |  |  |
Mevion Medical Systems Inc | Insurance Settlement Receivable Current |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Cost of repairs | $ 977,000 |  |  |
Maximum |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Stock options exercise price (in dollars per share) | $ 3.90 | $ 3.90 |  |
Maximum | Medical and Office equipment |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Property equipment, useful life | 10 years |  |  |
Minimum |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Stock options exercise price (in dollars per share) | $ 2.68 | $ 2.82 | $ 3.90 |
Minimum | Customer Three | Accounts Receivable |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Concentration risk, percentage | 10.00% | 10.00% |  |
Minimum | Medical and Office equipment |  |  |  |
Accounting Policies [Line Items] |  |  |  |
Property equipment, useful life | 3 years |  |  |

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