Equity Plan - Unrecognized Compensation Cost - Nonvested Stock Options (Details) - Options $ in Thousands	9 Months Ended
Sep. 30, 2021 USD ($)
Unrecognized Compensation Cost
Total unrecognized compensation cost related to nonvested stock options granted	$ 1,263
Expected weighted-average period for recognition of compensation costs related to nonvested stock options	2 years 9 months 14 days

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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