Stockholders' Equity (Details) - USD ($)	1 Months Ended
	Nov. 30, 2013	Jun. 28, 2015	Dec. 28, 2014	Jul. 31, 2013
Class of Stock [Line Items]
Common stock, shares authorized (in shares)		100,000,000	100,000,000
Preferred stock, shares authorized (in shares)		10,000,000	10,000,000
Maximum offering				$ 40,000,000.0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Closing stock price (in dollars per share)	$ 2.90	$ 1.61
Proceeds from offering	$ 23,100,000
Stock issuance cost	$ 2,200,000
Warrants outstanding (in warrants)		2,300,000
November 2009 financing
Class of Stock [Line Items]
Warrants outstanding (in warrants)		1,900,000
Exercise price of warrants (in dollars per unit)		$ 2.15
June 2012 financing
Class of Stock [Line Items]
Warrants outstanding (in warrants)		2,300,000
Exercise price of warrants (in dollars per unit)		$ 2.98
Common stock
Class of Stock [Line Items]
Shares issued in aggregate (in shares)	8,740,000