Fair Value Measurements (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2020

Dec. 31, 2019

Fair Value Measurements

Fair value hierarchy for financial assets and liabilities

The following tables present the Company’s fair value hierarchy for financial assets and liabilities measured as of September 30, 2020 and December 31, 2019 ($ in millions):

	September 30, 2020
	Level 1		Level 2		Level 3		Total
Assets:
U.S. Government obligations	$	—	$	6.7	$	—	$	6.7
Total	$	—	$	6.7	$	—	$	6.7

	December 31, 2019
	Level 1		Level 2		Level 3		Total
Assets:
U.S. Government obligations	$	—	$	5.9	$	—	$	5.9
Total	$	—	$	5.9	$	—	$	5.9

The following tables present the Company’s fair value hierarchy for financial assets and liabilities measured as of December 31, 2018 and 2019 ($ in millions):

	Fair Value Measurements
	as of December 31, 2018
		Level 1		Level 2		Level 3		Total
Assets:
U.S. Government obligations	$	—	$	3.2	$	—	$	3.2
Total	$	—	$	3.2	$	—	$	3.2

	Fair Value Measurements
	as of December 31, 2019
	Level 1		Level 2		Level 3		Total
Assets:
U.S. Government obligations	$	—	$	5.9	$	—	$	5.9
Total	$	—	$	5.9	$	—	$	5.9

Schedule of reconciliation of movements in preferred stock warrant liability

	Preferred Stock
	Warrant Liability
Balance as of December 31, 2017	$	0.4
Change in fair value		0.2
Exercise of preferred stock warrants		(0.6)
Balance as of December 31, 2018	$	—