Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($) Customer	Dec. 31, 2016 USD ($) Customer	Jan. 02, 2016 USD ($) Customer	Jan. 03, 2015 USD ($) Customer
Disclosure Summary Of Significant Accounting Policies [Line Items]
Provision of sales returns	$ 44,000	$ 44,000	$ 60,000
Gross value of demos and loaners	1,600,000	1,600,000	1,600,000
Accumulated amortization on inventory demos and loaners	490,000	$ 490,000	575,000
Estimated useful life of demos and loaners		4 years
Estimated useful lives of the assets		3 years
Non-cash impairment charges		$ 120,000
Products warranty period		2 years
Shipping and handling costs		$ 300,000	300,000	$ 300,000
Advertising and promotion costs		100,000	$ 100,000	$ 200,000
Accrued interest and penalty incurred	$ 0	$ 0
Customer accounted percentage of net accounts receivable balance		10.00%	10.00%
Revenue, Total | Customer Concentration Risk
Disclosure Summary Of Significant Accounting Policies [Line Items]
Number of customer accounted for total revenues and net accounts receivable | Customer	0	0	0	0
Customer accounted percentage of total revenues		10.00%	10.00%	10.00%
Accounts Receivable | Credit Concentration Risk
Disclosure Summary Of Significant Accounting Policies [Line Items]
Number of customer accounted for total revenues and net accounts receivable | Customer	0	0	0
Ocunetics Patent
Disclosure Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment charges	$ 120,000