NOTES PAYABLE - Summary of Notes Payable (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Less: Current portion	$ (17,994)	$ (3,273)	$ 0
Total	7,369	1,364	$ 0
Equipment Finance Agreement [Member]
Notes Payable	25,363	4,637
Less: Current portion	(17,994)	(3,273)
Total	7,369	1,364
Miner Equipment Note A [Member] \| Equipment Finance Agreement [Member]
Notes Payable	$ 1,992	$ 4,233
Loan Date	December 2020
Maturity Date	June 2022	July 2022
Interest Rate	17.00%	17.00%
Initial Financing	$ 4,482	$ 4,482
Miner Equipment Note B [Member] \| Equipment Finance Agreement [Member]
Notes Payable	$ 166	$ 404
Loan Date	December 2020
Maturity Date	June 2022	June 2022
Interest Rate	17.00%	17.00%
Initial Financing	$ 428	$ 428
Miner Equipment Note C [Member] \| Equipment Finance Agreement [Member]
Notes Payable	$ 1,733
Loan Date	March 2021
Maturity Date	November 2022
Interest Rate	17.00%
Initial Financing	$ 2,229
Miner Equipment Note D [Member] \| Equipment Finance Agreement [Member]
Notes Payable	$ 3,343
Loan Date	April 2021
Maturity Date	December 2022
Interest Rate	17.00%
Initial Financing	$ 4,012
Miner Equipment Note E And H [Member] \| Equipment Finance Agreement [Member]
Notes Payable	$ 11,751
Loan Date	May 2021
Maturity Date	October 2023
Interest Rate	15.00%
Initial Financing	$ 12,080
Miner Equipment Note I [Member] \| Equipment Finance Agreement [Member]
Notes Payable	$ 3,962
Loan Date	July 2021
Maturity Date	January 2023
Interest Rate	17.00%
Initial Financing	$ 4,457
Miner Equipment Note J [Member] \| Equipment Finance Agreement [Member]
Notes Payable	$ 2,415
Loan Date	July 2021
Maturity Date	March 2023
Interest Rate	17.00%
Initial Financing	$ 2,701

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Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Carrying value as of the balance sheet date of notes payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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