Revenue - Narrative (Details) - USD ($) |
3 Months Ended | 9 Months Ended | |
|---|---|---|---|
Sep. 29, 2018 |
Sep. 29, 2018 |
Dec. 30, 2017 |
|
| Revenue, Initial Application Period Cumulative Effect Transition [Line Items] | |||
| Accumulated deficit | $ (172,632,000) | $ (172,632,000) | $ (177,145,000) |
| Deferred revenue, revenue recognized | 17,600,000 | ||
| Capitalized contract cost | 900,000 | 900,000 | |
| Capitalized contract cost, amortization | $ 22,000 | $ 61,000 | |
| Accounting Standards Update 2014-09 | |||
| Revenue, Initial Application Period Cumulative Effect Transition [Line Items] | |||
| Accumulated deficit | $ 100,000 | ||
| Customer Contracts | |||
| Revenue, Initial Application Period Cumulative Effect Transition [Line Items] | |||
| Weighted-Average Remaining Life (Years) | 5 years |