Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Income tax benefit	$ 0	$ 0
Provision to income tax expense for TCJA			$ 18,894,000
Impact to effective tax rate		0.00%
Government research and development tax credits	8,141,000	$ 6,917,000
Unrecognized tax benefits	0	$ 0
Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Government research and development tax credits	8,141,000
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	165,623,000
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 165,115,000