Nature of Business and Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($)	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement or change in accounting principle, cumulative effect of change on equity or net assets	$ 6,500,000
Cumulative effect adjustment for adoption of new accounting guidance			$ 0
Accounting standards update 2016-09, excess tax benefit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards		$ 410,800,000
Deferred income tax assets, net			3,400,000
Domestic Tax Authority | Accounting standards update 2016-09, excess tax benefit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards		404,700,000
State and Local Jurisdiction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards	880,700,000
State and Local Jurisdiction | Accounting standards update 2016-09, excess tax benefit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards		$ 6,100,000
Accumulated Deficit | Accounting standards update 2016-09, forfeiture rate component
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance			$ (9,371,000)
Accumulated Deficit | Accounting standards update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance	0
Accumulated Deficit | Accounting standards update 2016-01, financial instruments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance	(25,100,000)
Accumulated Deficit | Accounting standards update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance	$ 0