STOCKHOLDERS' EQUITY, STOCK-BASED COMPENSATION AND NET LOSS PER SHARE - Narrative (Details) - USD ($)		12 Months Ended
	Mar. 29, 2019	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)		100,000,000	100,000,000
Weighted average grant date fair value of options			$ 12,800,000
Proceeds from stock options exercised			1,000,000.0
Intrinsic value of options exercised			$ 1,500,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option award expiration period		10 years
Weighted average grant date fair value of options		$ 335,000
2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)		525,000
2014 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)		10,000,000
2017 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)		10,000,000
Aspire Capital Fund, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)		11,999,597
Private Placement | Aspire Capital Fund, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for purchase	$ 30,000,000.0
Shares authorized for purchase (in shares)	50,000
Consecutive threshold trading days	10 days
Purchase price, daily maximum	$ 250,000
Purchase price, optional maximum daily amount (in shares)	3,000,000
Purchase amount, percentage of aggregate shares	30.00%
Threshold purchase price, percentage of closing stock price	80.00%
Purchase price per share, percentage of volume-weighted average stock price	97.00%
Threshold minimum stock price for purchase (in dollars per share)	$ 0.25
Sale of stock, shares authorized (in shares)	8,140,373
Shares authorized, percentage of common stock outstanding	19.99%
Minimum price per share to maintain average purchase price (in dollars per share)	$ 1.85
Shares issued (in shares)	629,370	4,129,370
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issuances		$ 10,800,000
Common Stock | Private Placement | Aspire Capital Fund, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of purchase	30 months