Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding, Beginning Balance (in shares)	3,838,060
Shares, Granted (in shares)	1,031,068
Shares, Exercised (in shares)	(109,826)
Shares, Forfeited or expired (in shares)	(15,784)
Shares, Outstanding, Ending Balance (in shares)	4,743,518		3,838,060
Shares, Exercisable (in shares)	2,397,928
Shares, Vested and expected to vest (in shares)	4,495,867
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted- Average Exercise Price, Outstanding, Beginning Balance (in dollars per share)	$ 18.93
Weighted- Average Exercise Price, Granted (in dollars per share)	20.43
Weighted- Average Exercise Price, Exercised (in dollars per share)	0.98
Weighted- Average Exercise Price, Forfeited or expired (in dollars per share)	26.97
Weighted- Average Exercise Price, Outstanding, Ending Balance (in dollars per share)	19.64		$ 18.93
Weighted- Average Exercise Price, Exercisable (in dollars per share)	15.08
Weighted- Average Exercise Price, Vested and expected to vest (in dollars per share)	$ 19.37
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted- Average Remaining Contractual Term, Outstanding	7 years 7 months 6 days		7 years
Weighted- Average Remaining Contractual Term, Exercisable	6 years 2 months 12 days
Weighted- Average Remaining Contractual Term, Vested and expected to vest	7 years 6 months
Aggregate Intrinsic Value, Outstanding, Ending Balance	$ 19,885
Aggregate Intrinsic Value, Exercisable	18,531
Aggregate Intrinsic Value, Vested and expected to vest	$ 19,697
Weighted-average grant-date fair value of options granted (in dollars per share)	$ 12.76
Intrinsic value of options exercised	$ 2,000
Cash received for options exercised	108	$ 224
Fair value of shares vested	3,100
Unrecognized compensation expense related to non-vested stock-options, net of related forfeiture estimates	$ 30,900
Unrecognized compensation expense recognition period	3 years

Unrecognized cost of unvested share-based compensation awards.

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.