Stock Option Plan (Tables)

12 Months Ended

Dec. 31, 2015

Transaction under Stock Option Plan

Transactions under the Plan for the years ending December 31, 2015, 2014, and 2013 were as follows:

(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding, December 31, 2012		7,147,303		$	4.11
Granted		2,649,900			3.28
Exercised		(570,168	)		1.68
Cancelled		(2,479,732	)		4.58
Outstanding, December 31, 2013		6,747,303			3.81
Granted		1,099,300			4.95
Exercised		(613,138	)		2.26
Cancelled		(727,801	)		4.54
Outstanding, December 31, 2014		6,505,664			4.07
Granted		427,800			10.47
Exercised		(3,249,160	)		3.95
Cancelled		(202,835	)		4.36
Outstanding, December 31, 2015		3,481,469		$	4.96		6.98	$	12,601
Vested and unvested expected to vest at December 31, 2015		3,443,414		$	4.24		5.84	$	12,463
Options exercisable, December 31, 2015		2,120,834		$	4.24		5.84	$	8,622
Options exercisable, December 31, 2014		3,781,162		$	4.10		5.80	$	4,130
Options available for future grant		2,768,230

Summary of Nonvested Restricted Stock

A summary of the status of non-vested restricted stock as of December 31, 2015, 2014 and 2013 is as follows:

	Number of Shares			Weighted-Average Grant Date Fair Value
Non-vested, December 31, 2012		733,739		$	4.37
Granted		75,272			4.34
Vested		(292,399	)		4.31
Cancelled		(163,747	)		4.42
Non-vested, December 31, 2013		352,865			4.38
Granted		66,828			5.07
Vested		(253,835	)		4.38
Cancelled		(21,350	)		4.41
Non-vested, December 31, 2014		144,508			4.70
Granted		1,590,574			9.01
Vested		(148,694	)		4.88
Cancelled		—			—
Non-vested, December 31, 2015		1,586,388		$	9.00