Stockholders' Equity - Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Jun. 26, 2016	Jul. 25, 2013	Dec. 31, 2013	Dec. 31, 2016	Jul. 02, 2013
Warrants to Purchase Common Stock
Exercise Price (in dollars per share)	$ 5.76
Warrants expired (in shares)	8,694
Conversion Of Stock Mandatorily Redeemable Convertible Preferred Stock Warrant Into Common Stock Warrant
Warrants to Purchase Common Stock
Warrants issued (in shares)					142,534
Preferred Stock Warrants
Warrants to Purchase Common Stock
Mark-to-market income related to the fair value measurement of the warrants			$ 313
Common Stock Warrants expiring February 8, 2020
Warrants to Purchase Common Stock
Number of common stock shares issued on conversion of warrants		17,607
Number of shares of common stock tendered to the Company		14,052
Exercise Price (in dollars per share)		$ 3.79
Common Stock Warrants expiring December 7, 2018
Warrants to Purchase Common Stock
Number of common stock shares issued on conversion of warrants		16,210
Number of shares of common stock tendered to the Company		19,321
Exercise Price (in dollars per share)		$ 4.64
Common Stock Warrants expiring June 7, 2017
Warrants to Purchase Common Stock
Number of common stock shares issued on conversion of warrants		30,250
Number of shares of common stock tendered to the Company		5,270
Exercise Price (in dollars per share)		$ 1.27
Common Stock Warrants expiring June 30, 2017
Warrants to Purchase Common Stock
Exercise Price (in dollars per share)				$ 2.46
Warrants Outstanding (in shares)				31,130
Common Stock
Warrants to Purchase Common Stock
Number of common stock shares issued on conversion of warrants		64,067