Revenue Recognition and Adoption of New Accounting Pronouncement - Summary of Revenues Disaggregated by Recognition at Point in Time and Over Time (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Contract Revenues | ||
| Total | $ 348 | $ 28 |
| Healios License Agreement [Member] | ||
| Contract Revenues | ||
| Product supply revenue | 227 | |
| Service revenue | 121 | |
| Total | 348 | |
| Recognized at Point in Time [Member] | Healios License Agreement [Member] | ||
| Contract Revenues | ||
| Product supply revenue | 227 | |
| Service revenue | 0 | |
| Total | 227 | |
| Recognized Over Time [Member] | Healios License Agreement [Member] | ||
| Contract Revenues | ||
| Product supply revenue | 0 | |
| Service revenue | 121 | |
| Total | $ 121 | |