STOCKHOLDERS' EQUITY - Additional information (Details)			12 Months Ended
	Dec. 08, 2021 USD ($) $ / shares shares	Oct. 22, 2021 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) item $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Aug. 31, 2021 USD ($)	Dec. 22, 2020 $ / shares	Dec. 31, 2019 USD ($) $ / shares shares
Capital Stock Shares authorized.			120,000,000
Common Stock, Shares Authorized			79,999,997	79,999,997
Common Stock, Par or Stated Value Per Share | $ / shares			$ 0.01	$ 0.01
Special Stock, Shares Authorized			1
Special Stock, Par or Stated Value Per Share | $ / shares			$ 0.01	$ 0.01
Excess Stock, Shares Authorized			1	1
Common Stock, Shares, Issued			43,024,424	38,345,540
Common Stock, Shares, Outstanding			36,626,549	32,172,107
Warrant liability | $			$ 1,146,000	$ 830,000
Warrants, term							10 years
Warrants to purchase common stock issued (in shares)	2,650,000						7,179,000
Warrants, Exercise Price (in dollars per share) | $ / shares	$ 1.90		$ 4.31			$ 4.31	$ 6.50
Threshold minimum beneficial ownership (as a percent)			5.00%				5.00%
Threshold maximum percentage of issued and outstanding common stock, after exercise of warrants (as a percent)							19.90%
Sale of common stock, net | $			$ 7,639,000
Unrealized loss on warrants | $			$ 73,000	$ 965,000
Number of board members who can be appointed by the warrant holder | item			1
Preemptive rights period			5 years
Share repurchase program, authorized amount | $							$ 5,000,000.0
Share repurchase program, number of shares repurchased (in shares)			250,197
Share repurchase program, average price paid per share (in dollars per share) | $ / shares			$ 1.93
Share repurchase program, approximate dollar value of shares available for purchase | $			$ 4,500,000
Stock repurchase program, shares repurchased, amount | $			483,361
Common Stock
Sale of common stock, net | $			$ 42,000
Shares issued			4,144,000
Series A And B Preferred Stock [Member]
Excess Stock, Shares Authorized			1
ATM Program
Stock Issuance Program, Maximum Amount Authorized | $					$ 10,000,000.0
ATM Program | Common Stock
Shares issued			701,327
Agreement with B. Riley | Common Stock
Gross proceeds from issuance of common stock | $			$ 1,400,000
Stock issuance costs, professional and brokerage fees | $			169,000
Value of common stock available for issuance | $			$ 8,600,000
Agreement with B. Riley | Common Stock | Weighted Average
Share price (in dollars per share) | $ / shares			$ 1.95
Private Placement
Shares issued		2,539,473
Share Price | $ / shares		$ 1.90
Gross proceeds | $		$ 4,800,000
Preferred Stock
Preferred Stock, Shares Authorized			2	2
Preferred Stock, Par or Stated Value Per Share | $ / shares			$ 0.01	$ 0.01
Blank Check Preferred Stock
Preferred Stock, Shares Authorized			40,000,000	40,000,000
Preferred Stock, Par or Stated Value Per Share | $ / shares			$ 0.01	$ 0.01
Special Stock, Shares Authorized			40,000,000
Rights Offering
Gross proceeds from issuance of common stock | $	$ 1,700,000
Shares issued	903,576