Stockholders' Equity (Details) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended		10 Months Ended
	Sep. 10, 2021	Jun. 18, 2021	Sep. 30, 2021	Feb. 19, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 10, 2021	Aug. 31, 2021	Jul. 31, 2020
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of common stock in at-the-market offering, net of issuance costs					$ 67,189,000	$ 0
Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price									$ 250,000,000
2020 Open Market Sales Agreement
Subsidiary, Sale of Stock [Line Items]
Commission on sale of stock per agreement (percent)					3.00%
Issuance of common stock in at-the-market offering (shares)	3,300,000	4,000,000		8,200,000	12,300,000		15,600,000
Proceeds from issuance of common stock in at-the-market offering, net of issuance costs					$ 68,700,000		$ 90,300,000
Weighted-average sales price per share					$ 5.58		$ 5.80
2020 Open Market Sales Agreement | Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price									$ 100,000,000
2021 Open Market Sales Agreement
Subsidiary, Sale of Stock [Line Items]
Commission on sale of stock per agreement (percent)			3.00%
Shares sold under agreement			0		0
2021 Open Market Sales Agreement | Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price								$ 150,000,000