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Equity - Narrative (Details)					1 Months Ended	3 Months Ended		12 Months Ended
	Aug. 06, 2020 USD ($)	Jul. 28, 2020 USD ($)	Jun. 11, 2020 USD ($) $ / shares shares	Dec. 18, 2019 USD ($) $ / shares shares	Aug. 31, 2017 USD ($)	Mar. 31, 2021 USD ($) vote $ / shares shares	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) $ / shares shares	Aug. 31, 2020 $ / shares
Subsidiary, Sale of Stock [Line Items]
Shares issued, value						$ 20,991,000	$ 1,141,000
Class of warrant or right, outstanding (in shares) | shares						12,378,016,000
Exercise price (in dollars per share) | $ / shares						$ 1.60			$ 2.54
Warrant liabilities						$ 45,455,000		$ 28,708,000
Common stock, shares authorized (in shares) | shares						200,000,000		200,000,000
Common stock, par value (in dollars per share) | $ / shares						$ 0.0001		$ 0.0001
Common stock, shares issued | shares						112,977,004		108,071,249
Common stock, shares outstanding | shares						112,977,004		108,071,249
Number of votes per share that common stockholders are entitled to | vote						1
Dividends declared or paid on common stock						$ 0
Exercise of common warrants
Subsidiary, Sale of Stock [Line Items]
Class of warrant or right, outstanding (in shares) | shares						292,469,000
August 2020 Shelf Registration Statement
Subsidiary, Sale of Stock [Line Items]
Sale common stock	$ 200,000,000.0
At-The-Market Offering
Subsidiary, Sale of Stock [Line Items]
Sale common stock					$ 50,000,000.0
Sale of stock, number of shares issued in transaction (in shares) | shares						4,706,844		1,069,486
Share price (in dollars per share) | $ / shares						$ 4.59		$ 2.16
Shares issued, value						$ 20,900,000		$ 2,100,000
2020 Sale Agreement - At-the-Market Offering
Subsidiary, Sale of Stock [Line Items]
Sale common stock					$ 50,000,000.0
SOBI Purchase Agreement
Subsidiary, Sale of Stock [Line Items]
Sale common stock			$ 25,000,000.0
Sale of stock, number of shares issued in transaction (in shares) | shares			5,416,390
Share price (in dollars per share) | $ / shares			$ 4.6156
Sale of stock, percentage of ten-day volume weighted average price of common stock			120.00%
Lock-up from closing, term						1 year
Redemption premium		$ 14,500,000
December 2019 Financing
Subsidiary, Sale of Stock [Line Items]
Sale common stock				$ 65,600,000
Sale of stock, number of shares issued in transaction (in shares) | shares				37,634,883
Share price (in dollars per share) | $ / shares				$ 1.46
Class of warrant or right, outstanding (in shares) | shares				22,988,501
Warrant Issued				$ 40,700,000
Issuance costs							4,400,000
Warrant liabilities						$ 45,500,000
Warrant, increase (decrease) in equity, amount						$ (16,700,000)	$ (800,000)
December 2019 Financing | Pre-Funded Warrant
Subsidiary, Sale of Stock [Line Items]
Class of warrant or right, number of warrants exercised (in shares) | shares				8,342,128
Exercise price (in dollars per share) | $ / shares				$ 0.0001
December 2019 Financing | Common Warrant
Subsidiary, Sale of Stock [Line Items]
Share price (in dollars per share) | $ / shares				0.125
Exercise price (in dollars per share) | $ / shares				$ 1.46
2017 PIPE
Subsidiary, Sale of Stock [Line Items]
Common stock, shares authorized (in shares) | shares						200,000,000
Common stock, par value (in dollars per share) | $ / shares						$ 0.0001

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