Summary of Significant Accounting Policies - Other (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Summary of Significant Accounting Policies
Emerging growth company, annual revenue threshold	$ 1,070.0
Value of common stock that is held by non-affiliates, that must be in excess of, in determining whether the Company is deemed to be a large accelerated filer and whether the Company will remain an emerging growth company	700.0
Value of non-convertible debt securities, in excess of, that was issued during the prior three-year period, in determining whether the Company will remain an emerging growth company	$ 1.0
Period for issuance of non-convertible debt securities in determining the threshold value of securities issued and whether the Company will remain an emerging growth company	3 years