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Related Party Transactions - Narrative (Details) |  |  |  |  |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 30, 2015 USD ($) shares | Oct. 28, 2015 USD ($) | Aug. 04, 2015 USD ($) shares | Jul. 31, 2015 USD ($) | May 13, 2015 USD ($) shares | May 07, 2015 USD ($) | Apr. 29, 2015 | Feb. 19, 2015 USD ($) | Jan. 22, 2015 shares | Feb. 28, 2013 | Dec. 31, 2014 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) shares | Dec. 31, 2015 USD ($)
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Royalty rate |  |  |  |  |  |  |  |  |  | 2.50% |  |  |  |
Termination notice, number of days |  |  |  |  |  |  |  |  |  |  |  | 120 days |  |
Repurchase of common stock | $ 5,000,000.0 |  | $ 5,000,000.0 |  | $ 5,000,000.0 |  |  |  |  |  |  |  | $ 23,704,000 | $ 16,071,000
Repurchase of common stock (in shares) | shares | 106,264 |  | 162,442 |  | 186,519 |  |  |  |  |  |  |  | 903,031 |
Director | George Broady |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Treasury stock acquired rate |  | 0.4066 |  | 0.4085 |  | 0.4286 |  |  |  |  |  |  |  |
Repurchase of common stock |  |  |  |  |  |  |  | $ 1,100,000 |  |  |  |  |  |
Repurchase of common stock (in shares) | shares |  |  |  |  |  |  |  |  | 91,817 |  |  |  |  |
Shares repurchased per trading day | shares |  |  |  |  |  |  |  |  | 5,000 |  |  |  |  |
Director | George K. Broady |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repurchase of common stock |  | $ 1,400,000 |  | $ 1,500,000 |  | $ 1,500,000 |  |  |  |  |  |  |  |
Soothe | Broady Health Sciences |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Royalty rate |  |  |  |  |  |  | 2.50% |  |  |  |  |  |  |
Royalty expense |  |  |  |  |  |  |  |  |  |  | $ 11,700 | $ 1,400 | $ 3,400 | 7,000
Termination notice, number of days |  |  |  |  |  |  |  |  |  |  |  | 120 days |  |
ReStore [Member] | Broady Health Sciences |  |  |  |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Royalty expense |  |  |  |  |  |  |  |  |  |  |  | $ 306,000 | $ 475,000 | $ 555,000

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