Stockholders' Equity	6 Months Ended
Jul. 01, 2018
Equity [Abstract]
Stockholders' Equity	Note 7 — Stockholders' Equity Common Stock and Preferred Stock As of July 1, 2018, the Company is authorized to issue 200 million shares of common stock and has 10 million shares of authorized but unissued shares of preferred stock. Without any further vote or action by the Company's stockholders, the Board of Directors has the authority to determine the powers, preferences, rights, qualifications, limitations or restrictions granted to or imposed upon any wholly unissued shares of undesignated preferred stock. On April 26, 2017, the Company filed an Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to increase the number of authorized shares of common stock from 100 million to 200 million. The proposal for the amendment was approved by the Company’s stockholders at its 2017 Annual Meeting of Stockholders held on April 26, 2017. Issuance of Common Stock On December 6, 2016, the Company filed a shelf registration statement on Form S-3, as amended on March 15, 2017, under which the Company may, from time to time, sell securities in one or more offerings up to a total dollar amount of $40.0 million. The Company's shelf registration statement was declared effective on March 16, 2017. Under the shelf registration, on May 29, 2018, the Company issued an aggregate of 13.5 million shares of common stock, $0.001 par value and warrants to purchase up to an aggregate of 5.4 million shares of common stock in a confidentially marketed underwritten offering. The common stock and warrants were issued in units (the “Units”), with each Unit consisting of (i) one share of common stock and (ii) a warrant to purchase 0.40 of a share of common stock, at a price of $1.15 per Unit. The Company received total net proceeds from the offering of $13.9 million, net of underwriting discounts and other offering expenses of $1.6 million. The warrants are exercisable any time for a period of 60 months from the date of issuance on May 29, 2018, and are exercisable at a price of $1.38 per share. The Company allocated the proceeds between the common stock and the warrants based on the relative fair value of each on the date of issuance. The estimated grant date fair value was $0.57 per warrant and was calculated based on the following assumptions used in the Black-Scholes model: expected term of 5 years, risk-free interest rate of 2.58%, expected volatility of 52.75% and expected dividend of zero. Under the shelf registration, in March 2017, the Company issued an aggregate of 11.3 million shares of common stock, $0.001 par value, in an underwritten public offering at a price of $1.50 per share. The Company received net proceeds from this offering of approximately $15.2 million, net of underwriter's commission and other offering expenses. The Company previously issued 2.3 million warrants exercisable for the Company's common stock with a strike price of $2.98 in conjunction with a June 2012 financing. These warrants expired in June 2017.

Note 7 — Stockholders' Equity

Common Stock and Preferred Stock

As of July 1, 2018, the Company is authorized to issue 200 million shares of common stock and has 10 million shares of authorized but unissued shares of preferred stock. Without any further vote or action by the Company's stockholders, the Board of Directors has the authority to determine the powers, preferences, rights, qualifications, limitations or restrictions granted to or imposed upon any wholly unissued shares of undesignated preferred stock.

On April 26, 2017, the Company filed an Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to increase the number of authorized shares of common stock from 100 million to 200 million. The proposal for the amendment was approved by the Company’s stockholders at its 2017 Annual Meeting of Stockholders held on April 26, 2017.

Issuance of Common Stock

On December 6, 2016, the Company filed a shelf registration statement on Form S-3, as amended on March 15, 2017, under which the Company may, from time to time, sell securities in one or more offerings up to a total dollar amount of $40.0 million. The Company's shelf registration statement was declared effective on March 16, 2017.

Under the shelf registration, on May 29, 2018, the Company issued an aggregate of 13.5 million shares of common stock, $0.001 par value and warrants to purchase up to an aggregate of 5.4 million shares of common stock in a confidentially marketed underwritten offering. The common stock and warrants were issued in units (the “Units”), with each Unit consisting of (i) one share of common stock and (ii) a warrant to purchase 0.40 of a share of common stock, at a price of $1.15 per Unit. The Company received total net proceeds from the offering of $13.9 million, net of underwriting discounts and other offering expenses of $1.6 million.

The warrants are exercisable any time for a period of 60 months from the date of issuance on May 29, 2018, and are exercisable at a price of $1.38 per share. The Company allocated the proceeds between the common stock and the warrants based on the relative fair value of each on the date of issuance. The estimated grant date fair value was $0.57 per warrant and was calculated based on the following assumptions used in the Black-Scholes model: expected term of 5 years, risk-free interest rate of 2.58%, expected volatility of 52.75% and expected dividend of zero.

Under the shelf registration, in March 2017, the Company issued an aggregate of 11.3 million shares of common stock, $0.001 par value, in an underwritten public offering at a price of $1.50 per share. The Company received net proceeds from this offering of approximately $15.2 million, net of underwriter's commission and other offering expenses.

The Company previously issued 2.3 million warrants exercisable for the Company's common stock with a strike price of $2.98 in conjunction with a June 2012 financing. These warrants expired in June 2017.