Equity - Issuance of stock and warrants (Details) - USD ($) $ / shares in Units, $ in Thousands							12 Months Ended
	Dec. 03, 2020	Jun. 23, 2020	May 28, 2020	Apr. 15, 2020	Sep. 23, 2019	Jun. 18, 2019	Dec. 31, 2020	Dec. 31, 2019
Equity
Cashless exercise of warrants (Shares)		58,981
Common stock issued for professional services (Shares)			50,000
Common stock issued for professional services			$ 200
Institutional exercise of warrants (Shares)				5,085,834
Warrant exercise price (in dollars per share)				$ 0.12
Proceeds from exercise of warrants				$ 600			$ 679	$ 142
Warrants expired (in shares)							1	139
Private placements
Equity
Net proceeds from issuance of stock						$ 6,900
2019 private placement
Equity
Proceeds from exercise of warrants	$ 100
Stock issued (in shares)	290,000
Issuance of common stock upon exercise of warrants, net of transaction costs (in shares)	580,000
Series A warrants \| Private placements
Equity
Warrant exercise price (in dollars per share)						$ 2.64
Series B warrants \| Private placements
Equity
Warrant exercise price (in dollars per share)						2.40
Series C pre-funded warrants \| Private placements
Equity
Warrant exercise price (in dollars per share)						$ 0.12
Unregistered Shares \| Series E warrants \| Private placements
Equity
Number of shares in exchange of warrant exercise					3,333,334
Common Stock
Equity
Cashless exercise of warrants (Shares)							58,981
Issuance of common stock upon exercise of warrants, net of transaction costs (in shares)								118,440
Common Stock \| Private placements
Equity
Number of shares in exchange of warrant exercise					69,167
Stock issued (in shares)						130,000
Purchase price (in dollars per share)						$ 2.40
Common Stock \| 2018 institutional sales of common stock and warrants, net of issuance costs
Equity
Stock issued (in shares)								199,167
Common Stock \| 2019 private placement
Equity
Institutional exercise of warrants (Shares)							5,665,834
Common Stock \| Series A warrants \| Private placements
Equity
Number of shares in exchange of warrant exercise						3,333,334
Common Stock \| Series B warrants \| Private placements
Equity
Number of shares in exchange of warrant exercise						3,333,334
Common Stock \| Series C pre-funded warrants \| Private placements
Equity
Number of shares in exchange of warrant exercise						3,203,334
Common Stock \| Placement agent warrants \| Private placements
Equity
Number of shares in exchange of warrant exercise						233,334
Warrant exercise price (in dollars per share)						$ 3.00
Warrants \| Private placements
Equity
Proceeds from exercise of warrants					$ 6,900
Warrants \| Series B warrants \| Private placements
Equity
Number of warrants to be exercised early					3,333,334
Warrants \| Series C pre-funded warrants \| Private placements
Equity
Purchase price (in dollars per share)						$ 2.28
Warrants \| Series F prefunded warrants \| Private placements
Equity
Number of shares in exchange of warrant exercise					3,264,167
Warrants \| Series E warrants
Equity
Term of warrants					5 years
Warrants \| Series E warrants \| Private placements
Equity
Warrant exercise price (in dollars per share)					$ 6.00
Warrants \| Placement agent warrants
Equity
Warrant exercise price (in dollars per share)					$ 6.00
Number of warrants issued					233,334

ReShape Lifesciences Inc. 10-K