Development Derivative Liability - Narrative (Details)	1 Months Ended	3 Months Ended		15 Months Ended
	Jan. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) payment tranche $ / shares shares	Mar. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) payment tranche $ / shares shares	Dec. 31, 2020 USD ($) shares
Derivative [Line Items]
Common stock, shares issued (in shares) | shares		47,982,000		47,982,000	29,471,854
Common stock, shares issued, value		$ 48,000		$ 48,000	$ 29,000
Derivative
Derivative [Line Items]
Initial liability		2,100,000
Funding during the period		15,100,000
Change in fair value		1,400,000	$ 500,000
SFJ Agreement
Derivative [Line Items]
Potential milestones payment		$ 120,000,000.0
Cost of borrowing rate		16.00%
SFJ Pharmaceuticals
Derivative [Line Items]
Cost of borrowing rate		2.50%
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | SFJ Agreement
Derivative [Line Items]
Common stock, shares issued (in shares) | shares		2,200,000		2,200,000
Shares issued (in usd per share) | $ / shares		$ 6.50		$ 6.50
Common stock, shares issued term		10 years
Number of tranches | tranche		2		2
Common stock, shares issued, value		$ 7,900,000		$ 7,900,000
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | SFJ Agreement | Derivative
Derivative [Line Items]
Funding during the period		15,115,000
Change in fair value		$ 1,426,000
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | SFJ Agreement | Tranche A
Derivative [Line Items]
Common stock, shares issued (in shares) | shares		1,100,000		1,100,000
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | SFJ Agreement | Tranche B
Derivative [Line Items]
Common stock, shares issued (in shares) | shares		1,100,000		1,100,000
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | bentracimab | SFJ Agreement
Derivative [Line Items]
Additional payment for license				$ 62,300,000
Additional payment received for license agreement				$ 27,700,000
Initial payment received for license agreement		$ 10,000,000.0
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | bentracimab | United States Food And Drug Administration | SFJ Agreement
Derivative [Line Items]
Additional payment for license		325,000,000.0
Initial payment for license		$ 5,000,000.0
Number of additional annual payments | payment		7		7
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | bentracimab | European Medicines Agency | SFJ Agreement
Derivative [Line Items]
Additional payment for license		$ 205,000,000.0
Initial payment for license		$ 5,000,000.0
Number of additional annual payments | payment		7		7
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | bentracimab | Pharmaceuticals And Medical Devices Agency Of Japan And National Medical Productions Administration Of China | SFJ Agreement
Derivative [Line Items]
Additional payment for license		$ 59,000,000.0
Initial payment for license		$ 1,000,000.0
Number of additional annual payments | payment		8		8
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | bentracimab | Maximum | SFJ Agreement
Derivative [Line Items]
Potential milestones payment receivable	$ 120,000,000.0			$ 30,000,000.0