Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

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

Share-based compensation expense included in costs and expenses

	Years Ended December 31,
	2018		2017		2016
	(in thousands)
Share-based compensation expense:
Cost of revenues	$	23	$	78	$	67
Sales and marketing		982		1,703		1,777
Technology support		1,247		586		601
General and administrative		2,615		1,739		1,982
Share-based compensation expense		4,867		4,106		4,427
Amount capitalized to internal use software		1		3		15
Total share-based compensation expense	$	4,866	$	4,103	$	4,412

Fair value of stock options granted using the following weighted average assumptions

	Years Ended December 31,
	2018		2017		2016
Expected volatility		68%		62%		58%
Expected risk-free interest rate		2.6%		1.8%		1.2%
Expected life (years)		4.5		4.4		4.4

Outstanding stock options

	Number of Options			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(years)		(thousands)
Outstanding at December 31, 2017		2,745,284		$	11.50		3.9	$	4,089
Granted		2,056,700			3.16
Exercised		(28,467	)		3.39				70
Forfeited or expired		(1,427,451	)		9.96
Outstanding at December 31, 2018		3,346,066		$	7.10		4.3	$	450
Vested and expected to vest at December 31, 2018		3,169,280		$	7.31		4.2	$	420
Exercisable at December 31, 2018		1,762,987		$	10.15		2.6	$	255

Shares reserved for issuance

	Number of Shares
Stock options outstanding		3,346,066
Authorized for future grants under stock-based incentive plans		2,666,500
Reserved for exercise of warrants		1,552,330
Total		7,564,896