Nature of Business and Basis of Presentation - Initial Public Offering (Details) - Common Stock - IPO - USD ($) $ / shares in Units, $ in Millions |
12 Months Ended | |
|---|---|---|
Sep. 28, 2018 |
Dec. 31, 2018 |
|
| Subsidiary, Sale of Stock [Line Items] | ||
| Number of shares issued in transaction (in shares) | 2,563,046 | |
| Sale of stock, price per share (in dollars per share) | $ 12.50 | |
| Sale of stock, consideration received | $ 19.8 | |
| Underwriting discount and offering costs | $ (3.2) | $ (3.2) |
| Parent Company | ||
| Subsidiary, Sale of Stock [Line Items] | ||
| Number of shares issued in transaction (in shares) | 1,834,310 | |
| Affiliated Entity | Selling Shareholders | ||
| Subsidiary, Sale of Stock [Line Items] | ||
| Number of shares issued in transaction (in shares) | 728,736 |