STOCKHOLDERS' EQUITY - Additional Information (Details)										3 Months Ended		12 Months Ended
	Oct. 29, 2021 shares	Jul. 06, 2021 USD ($) director shares	Jun. 23, 2021 shares	Jan. 19, 2021 USD ($) shares	Jul. 16, 2020 USD ($) director shares	Jun. 12, 2019 USD ($) shares	Oct. 02, 2017 shares	Aug. 07, 2017 installment shares	Aug. 07, 2017 shares	Jun. 30, 2021 USD ($) shares	Mar. 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($) Vote $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	May 17, 2021 USD ($) $ / shares	Jan. 27, 2021 USD ($)	Aug. 18, 2020 USD ($) $ / shares	Jun. 11, 2020 USD ($)	Mar. 13, 2020 USD ($)	Jan. 05, 2020 shares	May 21, 2019 shares	Apr. 13, 2015 shares	Dec. 31, 2009 shares
STOCKHOLDERS' EQUITY
Number of shares issued during period | $												$ 33,277,000	$ 14,673,000
Stock repurchase , Authorized amount | $																	$ 2,400,000	$ 2,600,000
Net proceeds after associated fees and expenses | $												33,277,000	14,673,000
Stock Repurchased During Period, Value | $												$ 970,000	$ 3,612,000
Stock options to purchase common stock							37,500					40,917	878,643
Number of restricted shares												903,643	637,270
Share-based Compensation, Total | $												$ 565,000	$ 2,294,000
Share-based Compensation Arrangement by Share-based Payment Award Options exercised Number of Shares												229,756	1,032,922
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value | $ / shares												$ 2.77	$ 0.66
Number of non-executive directors, received awards | director		4			4
Restricted stock awards [Member]
STOCKHOLDERS' EQUITY
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures												101,057	1,649,394
Employee Service Share-based Compensation, Non-vested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition												9 months
Employee Service Share-based Compensation, Non-vested Awards, Total Compensation Cost Not yet Recognized, Stock Options | $												$ 233,000
Other than options, granted												101,000	1,649,000
Stock options
STOCKHOLDERS' EQUITY
Stock options to purchase common stock												41,000	879,000
Number of Options, Vested and expected to vest												3,770,000
Employee [Member]
STOCKHOLDERS' EQUITY
Stock options to purchase common stock								470,000	470,000
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures									575,262
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares												$ 1.45
Employee Service Share-based Compensation, Non-vested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition												5 months
Employee Service Share-based Compensation, Non-vested Awards, Total Compensation Cost Not yet Recognized, Stock Options | $												$ 75,000
Number of Installments | installment								3
Number of Options, Vested and expected to vest																			470,000
Employee [Member] | Share-based Compensation Award, Tranche One [Member]
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								33.00%
Employee [Member] | Share-based Compensation Award, Tranche Two [Member]
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								33.00%
Employee [Member] | Share-based Compensation Award, Tranche Three [Member]
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage								33.00%
Non-Executive Directors | Restricted stock awards [Member]
STOCKHOLDERS' EQUITY
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures												9,671	18,248
Non-Executive Directors | Restricted stock awards [Member] | Share-based Compensation Award, Tranche One [Member]
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage												50.00%
Non-Executive Directors | Restricted stock awards [Member] | Share-based Compensation Award, Tranche Two [Member]
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage												0.00%
Common Class D [Member]
STOCKHOLDERS' EQUITY
Common stock, par value (in dollars per share) | $ / shares														$ 0.001
Stock Repurchased During Period, Shares												6,715	3,208,288
Stock Repurchased During Period, Value | $												$ 39,000	$ 2,400,000
Repurchase Of Common Stock Price Per Share | $ / shares												$ 5.80	$ 0.76
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																					8,250,000
Additional shares authorized			5,519,575
Common Class D [Member] | Scenario, Plan [Member] | Open Market Sale Agreement [Member] | Maximum
STOCKHOLDERS' EQUITY
Aggregate offering price | $														$ 25,000,000.0
Common Class D [Member] | Stock Plan 2009 [Member]
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																						8,250,000
Common Class D [Member] | Stock Vest Tax Repurchase [Member]
STOCKHOLDERS' EQUITY
Stock Repurchased During Period, Shares												515,162	710,992
Stock Repurchased During Period, Value | $												$ 931,000	$ 1,200,000
Repurchase Of Common Stock Price Per Share | $ / shares												$ 1.81	$ 1.64
Common Class D [Member] | 2019 Equity and Performance Incentive Plan
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant												5,898,026								5,500,000
Common Class D [Member] | Chief Financial Officer [Member] | Share-based Compensation Award, Tranche Two [Member]
STOCKHOLDERS' EQUITY
Number of restricted shares						211,838
Other than options, granted						94,150
Common Class D [Member] | Chief Financial Officer [Member] | Restricted stock awards [Member] | Share-based Compensation Award, Tranche Two [Member]
STOCKHOLDERS' EQUITY
Stock options to purchase common stock						99,846
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures						224,654
Common Class D [Member] | Chief Financial Officer [Member] | Restricted stock awards [Member] | Share-based Compensation Award, Tranche Three [Member]
STOCKHOLDERS' EQUITY
Stock options to purchase common stock						108,333
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures | $						$ 243,750
Common Class D [Member] | Chief Administrative Officer [Member]
STOCKHOLDERS' EQUITY
Other than options, granted							37,500
Common Class D [Member] | Chairperson [Member] | Restricted stock awards [Member] | Share-based Compensation Award, Tranche Two [Member]
STOCKHOLDERS' EQUITY
Stock options to purchase common stock						174,971
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures						393,685
Common Class D [Member] | Chief Executive Officer and President [Member] | Restricted stock awards [Member] | Share-based Compensation Award, Tranche One [Member]
STOCKHOLDERS' EQUITY
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures						656,142
Common Class D [Member] | Chief Executive Officer and President [Member] | Restricted stock awards [Member] | Share-based Compensation Award, Tranche Three [Member]
STOCKHOLDERS' EQUITY
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures						711,914
Common Class D [Member] | Chief Executive Officer and President [Member] | Employees Stock Option [Member] | Share-based Compensation Award, Tranche One [Member]
STOCKHOLDERS' EQUITY
Stock options to purchase common stock						291,619
Common Class D [Member] | Chief Executive Officer and President [Member] | Stock options | Share-based Compensation Award, Tranche Three [Member]
STOCKHOLDERS' EQUITY
Stock options to purchase common stock						316,406
Common Class D [Member] | Non-Executive Directors | Restricted stock awards [Member]
STOCKHOLDERS' EQUITY
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		9,671			25,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures | $		$ 50,000			$ 50,000
Vesting period		2 years			2 years
Common Class D [Member] | David Kantor [Member] | Share-based Compensation Award, Tranche One [Member]
STOCKHOLDERS' EQUITY
Number of restricted shares						195,242
Other than options, granted						86,774
Common Class D [Member] | Cathy Hughes [Member] | Restricted stock awards [Member] | Share-based Compensation Award, Tranche Three [Member]
STOCKHOLDERS' EQUITY
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures						427,148
Common Class D [Member] | Cathy Hughes [Member] | Stock options | Share-based Compensation Award, Tranche Three [Member]
STOCKHOLDERS' EQUITY
Stock options to purchase common stock						189,843
Class A Common Stock [Member]
STOCKHOLDERS' EQUITY
Shares issued and sold	883,890
Number of votes | Vote												1
Additional shares authorized			2,000,000
Class A Common Stock [Member] | Current ATM Program
STOCKHOLDERS' EQUITY
Common stock, par value (in dollars per share) | $ / shares																$ 0.001
Aggregate offering price | $															$ 25,000,000.0	$ 25,000,000
Volume weighted average price | $ / shares													$ 5.39
Net proceeds after associated fees and expenses | $				$ 24,000,000.0						$ 21,200,000	$ 2,800,000		$ 14,700,000
Shares issued and sold				4,325,102						1,893,126	420,439		2,859,276
Number of additional shares issued and sold				1,465,825
Gross proceeds | $				$ 25,000,000.0						$ 22,000,000.0	$ 3,000,000.0
Class A Common Stock [Member] | 2019 Equity and Performance Incentive Plan
STOCKHOLDERS' EQUITY
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant												2,000,000
Common Stock Class B
STOCKHOLDERS' EQUITY
Common stock, par value (in dollars per share) | $ / shares												$ 0.001	$ 0.001
Number of votes | Vote												10
Common stock, shares issued												2,861,843	2,861,843
Common Stock Class C
STOCKHOLDERS' EQUITY
Common stock, par value (in dollars per share) | $ / shares												$ 0.001	$ 0.001
Shares converted	883,890
Common stock, shares issued												2,045,016