Fair Value Measurement - Assets and Liabilities at Fair Value (Details) - USD ($) |
Jun. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Contingent consideration | ||
| Liabilities: | ||
| Contingent consideration due to seller | $ (1,300,000) | |
| Contingent consideration | ||
| Assets: | ||
| Contingent consideration due from seller | 0 | |
| Fair Value, Measurements, Recurring | Contingent consideration | ||
| Liabilities: | ||
| Contingent consideration due to seller | (1,250,000) | $ (2,075,000) |
| Fair Value, Measurements, Recurring | Contingent consideration | Level 1 | ||
| Liabilities: | ||
| Contingent consideration due to seller | 0 | 0 |
| Fair Value, Measurements, Recurring | Contingent consideration | Level 2 | ||
| Liabilities: | ||
| Contingent consideration due to seller | 0 | 0 |
| Fair Value, Measurements, Recurring | Contingent consideration | Level 3 | ||
| Liabilities: | ||
| Contingent consideration due to seller | $ (1,250,000) | $ (2,075,000) |