Income Taxes - Narrative (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 132,158,000	$ 124,828,000
Net operating loss carryovers	90,085,000	87,877,000
Unrecognized tax benefits	5,785,000	16,953,000	$ 17,939,000
Unrecognized tax benefits that would impact effective tax rate	5,000,000
Income tax penalties and interest accrued	0	$ 0
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	377,400,000
Internal Revenue Service (IRS) | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credits carryforward	12,600,000
Internal Revenue Service (IRS) | Orphan Drug Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credits carryforward	21,900,000
California
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	146,300,000
California | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development tax credits carryforward	10,100,000
After 2017, No Expiration | Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	$ 114,100,000