Income Taxes - Effective Tax Rate Differs from the Statutory Federal Income Tax Rate (Details)	12 Months Ended
Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Company's effective tax rate differs from the statutory federal income tax rate
Income tax provision at statutory rate	34.00%	34.00%	34.00%
State income taxes, net of federal benefit	9.60%	(70.80%)	(68.00%)
Permanent differences	(1.50%)	12.00%	(1.10%)
Research and development credits	3.00%	(34.80%)	(2.60%)
Change in valuation allowance	(387.40%)		(613.50%)
Other	1.30%	(3.30%)	(2.40%)
Effective tax rate	(341.00%)	(62.90%)	(653.60%)

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32698-109319

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

+ References

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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