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Stockholders' Equity and Stock Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands |  |  | 12 Months Ended |  |
--- | --- | --- | --- | --- | ---
Jan. 22, 2022 | Jul. 01, 2017 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | May 12, 2020 | Jul. 06, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Total compensation cost for share-based payment arrangements |  |  | $ 972 | $ 1,200 | $ 1,500 |  |
Share-based compensation income tax benefit recognized |  |  | 213 | 341 | 389 |  |
Unrecognized compensation expense |  |  | $ 652 |  |  |  |
Period for recognizing unrecognized compensation expense |  |  | 2 years 3 months 18 days |  |  |  |
Excess tax benefits recorded as a reduction to income tax expense |  |  | $ 87 | $ 120 | 145 |  |
Percentage of share ownership defining an acquiring person |  |  |  |  |  |  | 10.00%
Preferred stock, authorized (in shares) |  |  | 5,000,000 | 5,000,000 |  |  |
Preferred stock, no par value (in dollars per share) |  |  | $ 0 | $ 0 |  |  |
Subsequent event |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Dividends declared per common share (usd per share) | $ 0.24 |  |  |  |  |  |
Restricted stock award |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Total grant-date fair value of option shares vested |  |  | $ 1,000 | $ 1,200 | 1,200 |  |
Stock options |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Expiration period of grants |  |  | 10 years |  |  |  |
Total grant-date fair value of option shares vested |  |  | $ 514 | $ 484 | $ 473 |  |
Stock options | During 2016 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Award vesting period |  |  | 3 years |  |  |  |
Expiration period of grants |  |  | 10 years |  |  |  |
Stock options | Subsequent To January 1, 2015 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting percentage |  |  | 33.33% |  |  |  |
Performance shares |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Award vesting period |  |  | 3 years |  |  |  |
Minimum | Performance shares |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting percentage |  |  | 0.00% |  |  |  |
Maximum | Performance shares |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting percentage |  |  | 200.00% |  |  |  |
The Plan, 2020 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares approved to be issued in common stock (in shares) |  |  |  |  |  | 250,000 |
Number of shares available for future grants under plan (in shares) |  |  | 238,664 |  |  |  |
Employee Stock Purchase Plan, 2007 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares available for future grants under plan (in shares) |  |  | 377,475 |  |  |  |
Discount from closing market price at end of each quarter |  | 5.00% |  |  |  |  |
Employee Stock Purchase Plan, 2007 | Minimum |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Approved payroll deduction to purchase shares, percentage |  | 1.00% |  |  |  |  |
Employee Stock Purchase Plan, 2007 | Maximum |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Approved payroll deduction to purchase shares, percentage |  | 15.00% |  |  |  |  |
The 2017 Equity Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares available for future grants under plan (in shares) |  |  | 868,222 |  |  |  |
Common Stock | The Plan, 2020 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares awarded in period from plan (in shares) |  |  | 6,443 |  |  |  |
Common Stock | Director Stock Plan, 2010 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Shares awarded in period from plan (in shares) |  |  |  | 5,723 | 5,544 |  |
Series A Junior Participating Preferred Stock |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Preferred stock, authorized (in shares) |  |  | 1,000,000 |  |  |  |
Preferred stock, no par value (in dollars per share) |  |  | $ 0 |  |  |  |
Series A Junior Participating Preferred Stock |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Number of securities called by each right (in shares) |  |  |  |  |  |  | 0.005
Exercise price of rights (in dollars per share) |  |  |  |  |  |  | $ 0.9

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