Stock Options - Stock compensation expenses (Details) - Stock Incentive Plan 2017 - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Stock Options | ||
| Total stock compensation recognized, before taxes | $ 55 | $ 54 |
| Amount of unearned stock compensation related to unvested employee and non employee director share based awards | $ 295 | |
| Weighted average period over which the unearned stock compensation | 3 years | |
| General and administrative | ||
| Stock Options | ||
| Total stock compensation recognized, before taxes | $ 28 | 24 |
| Sales and marketing | ||
| Stock Options | ||
| Total stock compensation recognized, before taxes | 21 | 22 |
| Research and development | ||
| Stock Options | ||
| Total stock compensation recognized, before taxes | $ 6 | $ 8 |