Stockholders' Equity - Warrants Issued to Financial Institution, Vulcan, Service Provider (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended				12 Months Ended
	Dec. 31, 2015	Jun. 30, 2014	May 31, 2014	Nov. 30, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 29, 2013
Convertible Preferred Stock and Stockholders' Equity
Amount drawn on credit facility					$ 0	$ 0	$ 5,000
Warrant expense					$ 46	$ (803)	$ 9,861
Vulcan
Convertible Preferred Stock and Stockholders' Equity
Aggregate proceeds from issuance of Series A				$ 30,000
Common Stock Purchase Warrants | Service Provider
Convertible Preferred Stock and Stockholders' Equity
Exercise price of warrants (in dollars per share)			$ 12.81
Number of shares under warrant agreement (up to)	187,500		333,333
Vesting period			4 years
Expiration period			5 years
Early expiration period			12 months
Outstanding common stock warrants	145,833					145,833
Total number of warrants earned under agreement						112,500	33,333
Warrant expense							$ 1,700
Common Stock Purchase Warrants | Service Provider | Selling and Marketing Expense
Convertible Preferred Stock and Stockholders' Equity
Reduction in warrant expense						$ 1,000
Common Stock Purchase Warrants | Service Provider | Minimum
Convertible Preferred Stock and Stockholders' Equity
Expected life						1 year	4 years 4 months 24 days
Risk-free interest rate						0.52%	1.48%
Volatility (as a percent)						44.10%	54.80%
Common Stock Purchase Warrants | Service Provider | Maximum
Convertible Preferred Stock and Stockholders' Equity
Expected life						4 years	5 years
Risk-free interest rate						1.28%	1.55%
Volatility (as a percent)						48.90%	56.80%
Common Stock Purchase Warrants | Vulcan
Convertible Preferred Stock and Stockholders' Equity
Shares that may be purchased under warrant				666,666
Exercise price of warrants (in dollars per share)				$ 15.00
Common Stock Purchase Warrants | Revolving Credit Facility
Convertible Preferred Stock and Stockholders' Equity
Shares that may be purchased under warrant								66,666
Exercise price of warrants (in dollars per share)								$ 7.92
Number of shares exercised through a net settlement		66,666
Shares issued for exercise of warrants		27,526