Income Taxes - Reconciliation (Details)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	6.20%	6.10%	6.10%
Research and development tax credits	3.50%	4.10%	2.70%
Orphan drug tax credits	2.90%	2.30%	4.60%
Expiration of NOLs/Credits	(9.80%)	(29.80%)	(4.00%)
Permanent adjustments and other	(0.20%)	0.30%	(0.60%)
Stock based compensation	(9.40%)	0.00%	0.00%
Change in valuation allowance	(14.20%)	(4.00%)	(29.80%)
Effective income tax rate	0.00%	0.00%	0.00%

Effective income tax reconciliation net operating loss expirations.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
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Percentage of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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