WARRANTS - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended	6 Months Ended		12 Months Ended
	Aug. 31, 2015	Jul. 31, 2015	Mar. 31, 2018	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2018	Jan. 31, 2017	Sep. 30, 2016
Common Stock Warrants [Line Items]
Placement warrants not exercised and remained outstanding				2,036,733
Change in fair value of warrant liability				$ 4,701	$ (3,301)
March 2018 Direct Registered Offering | Common Stock
Common Stock Warrants [Line Items]
Issuance of common stock upon public offering, shares			4,090,000
March 2018 Direct Registered Offering | Series A Convertible Preferred Stock
Common Stock Warrants [Line Items]
Issuance of common stock upon public offering, shares			3,000,581
March 2018 Direct Registered Offering | Common Stock Warrants
Common Stock Warrants [Line Items]
Warrants issued			1,418,116
Exercise price			$ 8.31
Number of warrant exercised				0
Common stock warrants, expiration date			Mar. 31, 2025
Proceed from private placement and equity issuances, gross			$ 59,100
Fair value of warrants upon issuance			7,400
Allocated portion of proceeds from issuance of stock and warrants recorded in additional paid-in-capital			$ 6,600
2015 Placement Warrants
Common Stock Warrants [Line Items]
Warrants issued	198,760	198,760
Exercise price	$ 5.00	$ 5.00
Common stock warrants, expiry term	5 years	5 years
Number of warrant exercised						159,010
Stock issued during period						92,487
Number of warrant expired	39,750	39,750
Placement warrants not exercised and remained outstanding				0
2016 Placement Warrants
Common Stock Warrants [Line Items]
Warrants issued								1,380,745
Exercise price				$ 2.95
Common stock warrants, expiry term				7 years
Placement warrants not exercised and remained outstanding				536,711
2017 Placement Warrants
Common Stock Warrants [Line Items]
Warrants issued							1,720,512
Exercise price				$ 3.17
Common stock warrants, expiry term				7 years
Placement warrants not exercised and remained outstanding				1,500,022
2016 and 2017 Private Placement Warrants | Common Stock
Common Stock Warrants [Line Items]
Change in fair value of warrant liability				$ 4,700	$ (3,300)