Stock-Based Compensation and Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Assumptions for Estimating Fair Value of Stock Options

The following table summarizes the assumptions used for estimating the fair value of stock options granted under our equity plans for the years ended December 31:

	2017	2016	2015
Risk-free interest rate	2.32% - 2.42%	1.40% - 2.54%	1.65% - 2.13%
Expected term (years)	5.0	5.0 - 6.0	5.5 - 6.0
Expected volatility	42% - 44%	46% - 54%	41% - 47%
Dividend yield	—%	—%	—%
Weighted-average grant date fair value per share	$1.66	$2.65	$5.70

Summary of Option Activity

The following is a summary of option activity for the year ended December 31, 2017:

	Number of Options		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2017	11,426,296		$	6.10	—	—
Granted	368,894		$	4.13	—	—
Exercised	(1,407,646	)	$	0.85	—	—
Forfeited	(1,310,438	)	$	8.55	—	—
Expired	(1,158,253	)	$	11.45	—	—
Outstanding at December 31, 2017	7,918,853		$	5.75	6.4	$	17,792
Exercisable at December 31, 2017	6,080,899		$	5.16	5.8	$	16,989
Vested or expected to vest as of December 31, 2017	7,876,541		$	5.75	6.4	$	17,778

Schedule of Activities of RSUs

The following table summarizes our activities of RSUs and PRSUs during the year ended December 31, 2017:

	Number of RSUs		Weighted-Average Grant Date Fair Value
Unvested at January 1, 2017	3,888,768		$	8.46
RSUs and PRSUs granted	2,074,077		$	4.63
RSUs vested	(770,664	)	$	8.50
RSUs forfeited/expired	(1,849,541	)	$	7.84
Unvested at December 31, 2017	3,342,640		$	6.18
Expected to vest after December 31, 2017	2,843,933		$	6.31

Schedule of Assumptions for Stock Purchase Rights Granted under ESPP

The assumptions used to calculate our Black-Scholes-Merton Option Pricing Model for each stock purchase right granted under the ESPP were as follows for the year ended December 31:

	2017		2016		2015
Risk-free interest rate	1.17	%	0.39	%	0.27	%
Expected term (years)	0.50		0.50		0.50
Expected volatility	37	%	52	%	42	%
Dividend yield	—	%	—	%	—	%

Schedule of Stock-based Compensation Expense

Stock-based compensation expense related to stock options, RSUs, PRSUs and the ESPP are included in the following line items in our accompanying consolidated statements of operations for the year ended December 31 (in thousands):

	2017		2016		2015
Sales and marketing	$	2,429	$	4,002	$	3,081
Technology and analytics	2,300		3,422		2,582
Processing and servicing	483		869		544
General and administrative	7,303		7,622		5,375
Total	$	12,515	$	15,915	$	11,582