STOCKHOLDERS' EQUITY-Common stock and warrants (Details)	Oct. 08, 2019 series $ / shares shares	Oct. 02, 2019	Mar. 31, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares	Oct. 01, 2019 $ / shares	Aug. 02, 2019	Sep. 09, 2016 $ / shares shares
Stockholders' equity
Shares issued	16,200,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001		$ 0.0001	$ 0.0001
Share price (in dollars per share) | $ / shares					$ 19.74
Percentage of shares of class of directors	85.00%
Number of warrants issued							4,700,000
Equivalent number shares of the warrants							4,700,000
Annualized Rate Of Increase To The Strike Price Of Warrants Issued	6.75	6.75
Exercise price (in dollars per share) | $ / shares							$ 14.04
Warrant term (in years)	3 years
Authorized shares of capital stock, after amendment of certificate of incorporation	101,000,000
Authorized shares of common stock, after amendment of certificate of incorporation	100,000,000		100,000,000	100,000,000
Number of series of warrants | series	3
Number of shares of common stock that can be purchased from warrants	1
Series A Warrants
Stockholders' equity
Number of warrants issued			1,800,000
Warrants issued	1,798,322
Exercise price (in dollars per share) | $ / shares	$ 40.17			$ 41.03
Series B Warrants
Stockholders' equity
Number of warrants issued			2,200,000
Warrants issued	2,247,985
Exercise price (in dollars per share) | $ / shares	$ 48.28			49.37
Series C Warrants
Stockholders' equity
Number of warrants issued			2,900,000
Warrants issued	2,890,271
Exercise price (in dollars per share) | $ / shares	$ 60.45			$ 61.89
The Restructuring Support Agreement
Stockholders' equity
Warrant term (in years)						3 years
Convertible Preferred stock
Stockholders' equity
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001
Authorized shares of preferred stock, after amendment of certificate of incorporation	1,000,000