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SUBSEQUENT EVENT (Details) - USD ($) | 1 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Subsequent Event [Line Items] |  |  |  |
Issuance of common stock in connection with at market offering, net of issuance costs |  | $ 19,295,000 | $ 86,017,000 | $ 1,060,000
2018 Sales Agreement |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Issuance of common stock in connection with at market offering, net of issuance costs (in shares) |  | 13,214,867 | 10,083,079 |
Issuance of common stock in connection with at market offering, net of issuance costs |  | $ 19,295,000 | $ 38,366,000 |
Subsequent Event | 2018 Sales Agreement |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Issuance of common stock in connection with at market offering, net of issuance costs (in shares) | 530,228 |  |  |
Issuance of common stock in connection with at market offering, net of issuance costs | $ 748,000 |  |  |

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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
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