Stockholders' Equity - Issuance of Common Stock and Warrants (Details) - USD ($)		1 Months Ended		3 Months Ended
	Mar. 28, 2017	Mar. 31, 2017	Mar. 31, 2016	Apr. 02, 2017	Apr. 03, 2016	Jan. 01, 2017	Dec. 09, 2016
Class of Stock [Line Items]
Shelf registration, maximum offering							$ 40,000,000.0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001		$ 0.001		$ 0.001
Underwritten public offering price (in dollars per share)	$ 1.50	$ 1.50	$ 1.00	$ 1.78
Net proceeds	$ 15,800,000	$ 15,800,000	$ 8,800,000	$ 17,069,000	$ 10,000,000
Warrants outstanding (in shares)				2,300,000
June 2012 financing
Class of Stock [Line Items]
Warrants outstanding (in shares)				2,300,000
Strike price of warrants (in dollars per share)				$ 2.98
Common stock
Class of Stock [Line Items]
Aggregate shares of common stock issued	11,300,000.0	11,333,333	10,000,000