Subsequent Events - Textual (Details) - Global Development, Option and License Agreement [Member] - Nestec Ltd. (Nestle Health Sciences) [Member] - Subsequent Event [Member] $ in Millions	Oct. 12, 2017 USD ($)
Subsequent Event [Line Items]
Milestone revenue	$ 14
Term of collaborative research and development agreement	30 days
License option exercisable revenue	$ 3
License option exercisable, period	60 days
Sales-Based Milestone [Member]
Subsequent Event [Line Items]
Target sales for sales-based milestone revenue	$ 1,000
Maximum [Member] | Research and Development Agreement [Member]
Subsequent Event [Line Items]
Milestone revenue	90
Maximum [Member] | Sales-Based Milestone [Member]
Subsequent Event [Line Items]
Milestone revenue	$ 250