Common Stock and Stockholders' Equity - Capitalization (Details) - Follow-On Offering $ / shares in Units, $ in Millions	Jan. 24, 2017 USD ($) $ / shares shares
Capitalization
Follow-on Offering (in shares) | shares	7,887,500
Price of stock issued (in dollars per share) | $ / shares	$ 16.75
Proceeds received, net of issuance costs	$ 123.9
Underwriting discounts and commissions	7.6
Other offering expenses	$ 0.6