COMMON STOCK - Common Stock Issued, Net of Issuance Costs (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions				3 Months Ended
	Aug. 20, 2021	Dec. 04, 2020	Apr. 14, 2017	Mar. 31, 2022	Mar. 31, 2021
Net proceeds from common stock				$ 15,556	$ 72,203
2020 Lincoln Park PA
Maximum aggregate offering price		$ 100,000
Period for financing from common stock		36 months
Number of common stock issued				3.8
Net proceeds from common stock				$ 24,900
Threshold average sale price per share of common stock		$ 6.15
2020 Purchase Agreement with Lincoln Park | Maximum
Percentage of common stock issuable		19.99%
2020 Purchase Agreement with Lincoln Park | Lincoln Park
Minimum percentage considered for not to sale common stock		9.99%
ATM Offering Agreement
Number of common stock issued				7.4	9.3
Net proceeds from common stock	$ 50,000			$ 15,600	$ 47,300
Gross proceeds from issuance of common stock				$ 18,400
ATM Offering Agreement | Cantor Fitzgerald & Co | Maximum
Sales commission percentage			2.50%