CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue
Net earned premium	$ 29.2		$ 13.3		$ 54.5	$ 23.8
Ceding commission income	0.4		0.0		0.4	0.0
Net investment income	0.2		0.5		1.1	1.0
Commission income	0.1		0.0		0.1	0.0
Total revenue	29.9		13.8		56.1	24.8
Expense
Loss and loss adjustment expense, net	20.5		9.9		38.7	17.8
Other insurance expense	4.0		2.2		7.3	4.1
Sales and marketing	16.1		19.0		35.3	37.4
Technology development	4.2		2.1		7.7	3.6
General and administrative	5.8		3.6		24.0	6.4
Total expense	50.6		36.8		113.0	69.3
Loss before income taxes	(20.7)		(23.0)		(56.9)	(44.5)
Income tax expense	0.3		0.1		0.6	0.2
Net loss	(21.0)	$ (36.5)	(23.1)	$ (21.6)	(57.5)	(44.7)
Other comprehensive income, net of tax
Unrealized gain on investments	0.2	$ 0.0	0.0	$ 0.0	0.2	0.0
Comprehensive loss	$ (20.8)		$ (23.1)		$ (57.3)	$ (44.7)
Per Share Data:
Net loss per share attributable to common stockholders—basic and diluted (usd per share)	$ (1.77)		$ (2.09)		$ (4.89)	$ (4.05)
Weighted average common shares outstanding—basic and diluted (shares)	11,891,979		11,072,985		11,750,198	11,028,667