NATURE OF OPERATIONS AND GOING CONCERN, BASIS OF PRESENTATION AND RECENT ACCOUNTING PRONOUNCEMENTS - Reverse Stock Split (Details) $ / shares in Units, $ in Thousands			3 Months Ended
	May 06, 2022 location	Apr. 26, 2022	Mar. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares	Feb. 11, 2020 $ / shares
Cash and cash equivalents			$ 15,176		$ 19,031
Common stock, par value (in dollars per share) | $ / shares			$ 0.00001		$ 0.00001	$ 0.00001
Proceeds from Warrant Exercises				$ 8,509
Common Stock, Shares Authorized | shares			2,000,000		2,000,000
Going concern			false
Reverse stock split			On April 26, 2022, the Company effected a reverse stock split of its common stock, par value $0.00001 per share, at a ratio of 1-for-25 (the “2022 Reverse Stock Split”). As a result of the 2022 Reverse Stock Split, (i) every 25 shares of the issued and outstanding common stock were automatically converted into one newly issued and outstanding share of common stock, without any change in the par value per share; (ii) the number of shares of common stock into which each outstanding warrant or option to purchase common stock is exercisable was proportionally decreased, and (iii) the number of authorized shares of common stock outstanding was proportionally decreased. Shares of common stock underlying outstanding stock options and other equity instruments convertible into common stock were proportionately reduced and the respective exercise prices, if applicable, were proportionately increased in accordance with the terms of the agreements governing such securities.
Subsequent event
Reverse stock split ratio		0.04
Number of clinical sites | location	16