STOCKHOLDERS' EQUITY (DEFICIT) - Reserve Shares of Common Stock (Details) - shares |
Jun. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Class of Stock [Line Items] | ||
| Capital shares reserved for future issuance (in shares) | 28,842,532 | 12,981,599 |
| Stock Options Outstanding | ||
| Class of Stock [Line Items] | ||
| Capital shares reserved for future issuance (in shares) | 7,507,338 | 7,117,002 |
| Warrants to Purchase Common Stock | ||
| Class of Stock [Line Items] | ||
| Capital shares reserved for future issuance (in shares) | 17,035,214 | 1,914,316 |
| Conversion Debt | ||
| Class of Stock [Line Items] | ||
| Capital shares reserved for future issuance (in shares) | 1,745,897.23076923 | 1,720,224 |
| Omnibus Incentive Plan 2012 | ||
| Class of Stock [Line Items] | ||
| Capital shares reserved for future issuance (in shares) | 2,554,083 | 2,230,057 |