Acquisition of Metromile - Schedule of Fair Value of Consideration Transferred (Details) - Metromile $ / shares in Units, $ in Millions	Jul. 28, 2022 USD ($) $ / shares shares
Business Acquisition [Line Items]
Metromile issued and outstanding stock exchanged for Lemonade common stock	$ 136.9
Contingent consideration	0.0
Metromile vested awards exchanged for Lemonade awards	0.8
Total purchase consideration	$ 137.7
Shares issued for acquisition (in shares) \| shares	6,901,934
Business acquisition, share price (usd per share) \| $ / shares	$ 19.84
Remaining replacement awards, fair value	$ 4.3
Options to purchase common stock
Business Acquisition [Line Items]
Remaining replacement awards, fair value	0.1
RSUs
Business Acquisition [Line Items]
Remaining replacement awards, fair value	$ 4.2

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of liability recognized arising from contingent consideration in a business combination.

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