Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance [Line Items]
Operating Loss Carryforwards	$ 215,300,000	$ 108,800,000
Effective Income Tax Rate Reconciliation, Deduction, Percent	80.00%
Federal research income tax credits, gross of valuation allowance	$ 8,300,000	5,800,000
State research income tax credits, gross of valuation allowance	1,000,000	2,000,000
Operating loss carryforwards, various states	147,500,000	35,600,000
Federal tax benefit at statutory rate	(26,468,000)	(12,617,000)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	(5,570,000)	(1,842,000)
Unrecognized Tax Benefits	$ 945,000	603,000	$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Unrecognized Tax Benefits, Period Increase (Decrease)	$ 246,000	228,000
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	96,000	375,000
Net operating losses	55,110,000	25,372,000
Deferred Tax Assets, Tax Credit Carryforwards, Research	8,309,000	5,426,000
Stock compensation	1,092,000	267,000
Other temporary differences	4,648,000	1,679,000
Valuation allowance	(68,950,000)	(32,662,000)	$ (14,124,000)
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	(36,288,000)	(18,538,000)
Total deferred tax assets	209,000	82,000
Fixed and intangible assets	(155,000)	(82,000)
Deferred Tax Liabilities, Other	(54,000)	0
Total deferred tax liabilities	(209,000)	(82,000)
Net deferred tax assets	0	0
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	36,288,000	18,538,000
Benefit from income taxes	(458,000)	0
Income Tax Examination, Penalties and Interest Expense	0
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount	(2,912,000)	(2,279,000)
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions	342,000	603,000
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	169,000	45,000
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount	683,000	76,000
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount	(3,278,000)	(2,470,000)
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	0	(63,000)
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ 339,000	$ 9,000