Income Taxes - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) ownershipChange	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2011 USD ($)	Aug. 31, 2006 USD ($)
Operating Loss Carryforwards [Line Items]
Number of changes in ownership | ownershipChange	3
Income tax provision (benefit)	$ (17,425,000)	$ 0	$ 0
Increase (decrease) in deferred tax asset valuation allowance	25,100,000	33,500,000
Net deferred tax liability	0	17,425,000
Less valuation allowance	176,594,000	151,544,000
Unrecognized tax benefits that, if recognized, would affect effective tax rate	0	0
Interest or penalties recorded	0	0	0
Interest or penalties accrued	0	$ 0	$ 0
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating losses	526,900,000
Operating loss carryforwards that do not expire	272,300,000
Tax credit carryforward, amount	6,400,000
Operating loss carryforwards decrease				$ 121,100,000	$ 1,900,000
Tax credit carryforwards, decrease				3,000,000.0
Internal Revenue Service (IRS) | Drug Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	2,000,000.0
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating losses	343,200,000
Tax credit carryforward, amount	4,200,000
Operating loss carryforwards decrease				$ 53,300,000
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 290,700,000