STOCKHOLDERS’ EQUITY / DEFICIT - 2017 Employee Stock Purchase Plan (Details) - 2017 ESPP	12 Months Ended
	Dec. 31, 2017 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for issuance under the plan (in shares) | shares	380,000.000
Potential increase in shares available for issuance, as a percent of total outstanding common stock	1.00%
Maximum number of additional shares authorized for issuance (in shares) | shares	300,000
Purchase price of common stock, percent of fair market value	85.00%
Stock purchase offering period	6 months
Employee Stock Purchase Plan, Maximum Compensation	15.00%
Employee Stock Purchase Plan Annual Limit | $	$ 25,000
Shares reserved for future issuance (in shares) | $	$ 300,000