Stockholders' Equity - Equity Incentive Plans (Details)	3 Months Ended
Mar. 31, 2017 item shares	Mar. 31, 2016 shares
Equity Incentive Plans
Number of equity incentive plans \| item	2
Amended and Restated Equity Incentive Plan (The 1999 Plan)
Options disclosures
Granted (in shares)	0
Stock Incentive Plan 2015 (The 2015 Plan)
Equity Incentive Plans
Maximum number of shares authorized to be issued (in shares)	6,150,000
Options disclosures
Granted (in shares)	1,900,000	1,500,000

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant