Revenue Recognition - Deferred Revenue (Details) - USD ($) $ in Thousands  | 
Jun. 30, 2021  | 
Dec. 31, 2020  | 
|---|---|---|
| Revenue from Contract with Customer [Abstract] | ||
| Deferred extended maintenance and support | $ 2,568 | $ 2,902 | 
| Deferred royalties | 280 | 282 | 
| Deferred device and advances | 100 | 118 | 
| Total deferred revenues | 2,948 | 3,302 | 
| Less current portion | (1,422) | (1,496) | 
| Deferred revenues, non-current | $ 1,526 | $ 1,806 | 
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- Definition Deferred Extended Maintenance And Support No definition available. 
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- Definition Deferred Royalties No definition available. 
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- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount, after accumulated amortization, of deferred lease income. Includes, but is not limited to, amount paid in advance by lessee. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- References No definition available. 
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