401(k)	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
401(k)	401(k)The Company has a 401(k) retirement plan that covers all employees who have met certain eligibility requirements. The 401(k) plan provides for voluntary contributions by employees of up to 90% of their eligible compensation, subject to the maximum allowed by law. The Company is not required to make contributions to the plan but can make discretionary contributions. Beginning in the second half of 2021, all full-time Metromile employees have the option to contribute to the 401(k) retirement plan through the standard pre-tax or Roth in which the Company then offers a match of 3.5% funded with MILE (Metromile stock). The Company incurred expenses related to the 401(k) match of $0.8 million during the year ended December 31, 2021, $0.5 million of which was contributed to the plan in 2021 with the remaining amount to be contributed in the first quarter of 2022. The Company did not make any contributions to the plan during the year ended December 31, 2020.