Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Apr. 20, 2017 USD ($) $ / shares shares	Apr. 30, 2017 shares	Dec. 31, 2017 USD ($) vote $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Sep. 30, 2017 USD ($)	Mar. 31, 2017 shares	Dec. 31, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			50,000,000	50,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01
Number of authorized shares of preferred stock (in shares)			5,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01
Common stock, shares outstanding (in shares)			24,102,000	23,733,000
Preferred stock, shares outstanding (in shares)			0	0
Number of securities called by warrants or rights (in shares)	1,500,000
Number of votes per share | vote			1
Share repurchase program remaining repurchase amount | $			$ 15,300		$ 15,300
Purchase of treasury stock (in shares)	419,000		419,000	0
Increase in treasury shares (in shares)			103,000	76,000
Number of additional shares authorized and reserved for issuance (in shares)		4,000,000.0
Maximum shares of common stock authorized for issuance under stock option plan (in shares)		9,500,000.0				5,500,000.0
Proceeds from issuance of warrants | $	$ 2,200		$ 2,200	$ 0
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase shares outstanding under share based compensation (in shares)			2,933,232	861,366			778,590
Granted (in shares)			2,146,190	379,000
Weighted average grant date fair value of options granted (in dollars per share) | $ / shares			$ 1.69
Number of stock options granted (in shares)				0.94
Number of stock options exercised (in shares)			0	0
Unrecognized compensation cost | $			$ 734
Expected weighted-average period for recognized compensation cost			1 year 2 months 12 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $			$ 6,900
Expected weighted-average period for recognized compensation cost			1 year 6 months 26 days
RSUs | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $			$ 1,200
General and Administrative Expenses | Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $			3,200	$ 80
General and Administrative Expenses | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $			5,400	3,600
General and Administrative Expenses | RSUs | Habits at Work
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $			$ (57)	$ 1,100
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining to be granted under stock option plan (in shares)			3,300,000
Options to purchase shares outstanding under share based compensation (in shares)			5,700,000
Replacement Warrant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities called by warrants or rights (in shares)	1,500,000		1,500,000
Exercise price of warrants or rights (in dollars per share) | $ / shares	$ 2.50		$ 2.50
Proceeds from issuance of warrants | $	$ 700		$ 2,200