| Revenue Recognition - Deferred Revenue (Details) - USD ($) $ in Thousands | Jun. 30, 2020 | Dec. 31, 2019 | 
|---|---|---|
| Revenue from Contract with Customer [Abstract] | ||
| Deferred extended maintenance and support | $ 2,634 | $ 2,837 | 
| Deferred royalties | 285 | 290 | 
| Deferred device and rental revenues | 117 | 131 | 
| Customer deposits and advances | 15 | 23 | 
| Total deferred revenues | 3,051 | 3,281 | 
| Less current portion | (1,345) | (1,492) | 
| Deferred revenues, non-current | $ 1,706 | $ 1,789 | 
| X | ||||||||||
| 
- Definition Contract With Customers, Liability, Customer Deposits And Advances No definition available. 
 | 
| X | ||||||||||
| 
- Definition Deferred Extended Maintenance And Support No definition available. 
 | 
| X | ||||||||||
| 
- Definition Deferred Royalties No definition available. 
 | 
| X | ||||||||||
| 
- 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 
 | 
| X | ||||||||||
| 
- 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 
 | 
| X | ||||||||||
| 
- 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 
 | 
| X | ||||||||||
| 
- 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 
 | 
| X | ||||||||||
| 
- References No definition available. 
 |