Organization and Summary of Significant Accounting Policies - Narrative - Revenue Recognition (Details) |
12 Months Ended |
|---|---|
Dec. 31, 2017 | |
| Revenue Recognition, Multiple-deliverable Arrangements [Line Items] | |
| Period of time average selling prices are observed to establish best estimate of selling price | 12 months |
| Minimum [Member] | |
| Revenue Recognition, Multiple-deliverable Arrangements [Line Items] | |
| Product or service delivery period | 3 months |
| Maximum [Member] | |
| Revenue Recognition, Multiple-deliverable Arrangements [Line Items] | |
| Product or service delivery period | 6 months |