Notes Payable, Preferred Stock and Stock Purchase Warrants (Details)								3 Months Ended		12 Months Ended
	Jan. 31, 2021 USD ($) $ / shares shares	Jan. 21, 2021 USD ($) $ / shares shares	Nov. 09, 2020 USD ($) $ / shares	Aug. 09, 2020 USD ($) $ / shares shares	Apr. 24, 2020 USD ($) $ / shares shares	Apr. 22, 2020 USD ($)	Apr. 21, 2020 USD ($) $ / shares shares	Mar. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Apr. 30, 2022	Dec. 31, 2021 USD ($) $ / shares	May 09, 2021 $ / shares shares
Debt Instrument [Line Items]
Loss on extinguishment									$ (3,183,000)
Notes payable
Derivative assets								$ 269,000				$ 239,000
Carrying Amount								48,035,000				59,798,000
Derivative liabilities								$ 150,010,000				$ 236,291,000
Common stock, par value per share (in dollars per share) | $ / shares								$ 0.001				$ 0.001
Exchange Agreement with Highbridge
Debt Instrument [Line Items]
Warrants to purchase shares | shares					4,500,000		4,500,000
Exercise price of warrant (in dollars per share) | $ / shares					$ 0.66		$ 0.66
Notes payable
Shares issued | shares					11,026,086		11,026,086
Accrued and unpaid interest					$ 300,000		$ 300,000
2023 Notes.
Notes payable
Fair value of the embedded conversion option								$ 1,700,000				$ 5,800,000
PHC Notes
Notes payable
Principal amount				$ 35,000,000.0				35,000,000				35,000,000
Interest rate (as a percent)				9.50%							8.00%
Carrying Amount								16,419,000				15,277,000
Debt issuance costs and discounts				$ 1,400,000
Fair value of the embedded conversion option				$ 25,800,000				$ 104,000,000.0				149,100,000
Effective Interest Rate								9.50%	9.50%
Financing fee shares issued | shares				2,941,176
Common stock, par value per share (in dollars per share) | $ / shares				$ 0.001
Debt discount of financing fee shares				$ 1,500,000
Conversion rate				1,867.4136
Conversion price | $ / shares				$ 0.54
Conversion of Stock, Amount Issued				$ 15,000,000.0
Issuance costs incurred				2,900,000				$ 1,070,000				1,136,000
Amount of principal which is converted to shares				$ 1,000
PHC Notes | Debt Redemption on or After October 31, 2022
Notes payable
Threshold percentage of stock trigger				275.00%
Notice period				10 days
PHC Notes | Debt Redemption on or After October 31, 2023
Notes payable
Notice period				10 days
PHC Notes | Debt Redemption Six Months Prior to Maturity Date
Notes payable
Call premium percentage				130.00%
PHC Notes | Debt Redemption Within Six Months of Maturity Date
Notes payable
Call premium percentage				125.00%
2025 Notes
Notes payable
Fair value of the embedded conversion option								46,000,000.0				81,400,000
2025 Notes | Exchange Agreement with Highbridge
Notes payable
Principal amount					24,000,000.0		24,000,000.0
Deferred issuance costs and debt discounts					13,200,000
PPP Loan
Notes payable
Amount received from loan funding						$ 5,800,000
Principal amount								732,000				2,926,000
Interest rate (as a percent)						1.00%
Note term						2 years
Carrying Amount								$ 732,000				2,926,000
Effective Interest Rate								1.00%	1.00%
PPP Loan | Silicon Valley Bank
Notes payable
Principal amount						$ 5,800,000
Second Lien Notes
Notes payable
Original debt conversion amount										$ 15,700,000
Debt converted, Shares issued | shares										42,776,936
Second Lien Notes | Exchange Agreement with Highbridge
Notes payable
Principal amount					$ 15,700,000		$ 15,700,000
PHC Option | Put option
Notes payable
Derivative assets								$ 300,000				200,000
PHC Option | Put option | Maximum
Notes payable
Gain on fair value adjustment of derivatives								100,000
Energy Capital Facility
Debt Instrument [Line Items]
Exercise price of warrant (in dollars per share) | $ / shares													$ 0.3951
Notes payable
Deferred issuance costs and debt discounts										$ 7,600,000
Period to purchase stock			24 months
Derivative liabilities			$ 4,200,000					$ 47,700,000				$ 69,400,000
Energy Capital Facility | Maximum
Debt Instrument [Line Items]
Warrants to purchase shares | shares													10,000,000
Notes payable
Share price for debt conversion | $ / shares		$ 0.25
Cash Cash Equivalents and Other Available Credit Threshold		$ 8,000,000
Series B Preferred Stock
Notes payable
Number of shares sold pursuant to regular purchases | shares									0
Maximum amount of shares that can be purchased under the equity line agreement at purchase price									$ 12,000,000.0
Series B Preferred Stock | Energy Capital Facility
Notes payable
Preferred stock value			$ 12,000,000.0
Share price for debt conversion | $ / shares		$ 1,000.00
Number of shares sold pursuant to regular purchases | shares		0
Maximum amount of shares that can be purchased under the equity line agreement at purchase price		$ 12,000,000.0
Period to purchase stock		6 months
Daily limit		$ 4,000,000.0
Conversion price | $ / shares			$ 0.3951
Series A Preferred Stock
Notes payable
Debt converted, Shares issued | shares								25,783
Gain on extinguishment								$ 3,500,000
Series A Preferred Stock | Masters Capital
Notes payable
Shares issued | shares	22,783
Conversion price | $ / shares	$ 0.476
Amount of principal which is converted to shares	$ 1,000.00
Number of shares issued and sold | shares				3,000
Price per share (in dollars per share) | $ / shares	$ 1,000.00			$ 1,000.00
Additional shares issued | shares	22,783
Gross proceeds from stock	$ 22,800,000
Series A Preferred Stock | Masters Capital | Maximum
Notes payable
Shares issued | shares				27,000
Number of shares issued and sold | shares				27,000