Organization and Significant Accounting Policies - Organization (Details) $ in Thousands	12 Months Ended
Dec. 31, 2022 product item	Dec. 31, 2021 USD ($)
Organization and Significant Accounting Policies
Product pipeline, number of product candidates \| product	3
Number of reportable and operating segments \| item	1
Investments in marketable securities \| $		$ 0

Number of operating and reportable segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	chrs_NumberOfOperatingAndReportableSegments
Namespace Prefix:	chrs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration