Summary of Significant Accounting Policies - Narrative (Details)				1 Months Ended			3 Months Ended		9 Months Ended
	Apr. 08, 2019 USD ($)	Jan. 02, 2019	Mar. 02, 2016 USD ($)	Dec. 31, 2016 USD ($)	Feb. 28, 2016 USD ($) shares	Oct. 31, 2015 USD ($)	Sep. 28, 2019 USD ($) shares	Sep. 29, 2018 USD ($) $ / shares shares	Sep. 28, 2019 USD ($) shares	Sep. 29, 2018 USD ($) $ / shares shares	Jun. 29, 2019 USD ($)	May 06, 2019 USD ($) shares	May 05, 2019 $ / shares shares	Dec. 31, 2018 USD ($)
Class of Warrant or Right [Line Items]
Stock split, conversion ratio		1.5
Deferred offering costs, incurred							$ 2,500,000		$ 2,500,000		$ 4,900,000
Accrued stock issuance costs									$ 0
Warrants outstanding (in shares) | shares							0		0
Liability for estimated sales discounts							$ 2,200,000		$ 2,200,000					$ 800,000
Cost of goods sold							59,178,000	$ 21,235,000	$ 133,123,000	$ 46,709,000
Stock options granted (in shares) | shares									1,493,105
Common Stock | Line of Credit | SVB Credit Facilities
Class of Warrant or Right [Line Items]
Number of warrants issued (in shares) | shares								60,002		60,002			60,002
Exercise price (in dollars per share) | $ / shares								$ 3.00		$ 3.00			$ 3.00
Series B
Class of Warrant or Right [Line Items]
Number of warrants issued (in shares) | shares								121,694		121,694			121,694
Exercise price (in dollars per share) | $ / shares								$ 1.07		$ 1.07			$ 1.07
Series E
Class of Warrant or Right [Line Items]
Number of warrants issued (in shares) | shares								39,073		39,073			39,073
Exercise price (in dollars per share) | $ / shares								$ 3.68		$ 3.68			$ 3.68
IPO
Class of Warrant or Right [Line Items]
Deferred offering costs, incurred							2,500,000		$ 2,500,000			$ 4,900,000		$ 2,400,000
IPO | Common Stock
Class of Warrant or Right [Line Items]
Number of warrants issued (in shares) | shares												160,767
Shipping and Handling
Class of Warrant or Right [Line Items]
Cost of goods sold							$ 3,400,000	$ 2,100,000	$ 7,400,000	$ 4,900,000
Distributor One | Customer Concentration Risk | Revenue Benchmark
Class of Warrant or Right [Line Items]
Concentration risk							17.00%	39.00%	19.00%	38.00%
Distributor Two | Customer Concentration Risk | Revenue Benchmark
Class of Warrant or Right [Line Items]
Concentration risk							15.00%	22.00%	18.00%	17.00%
Distributor Three | Customer Concentration Risk | Revenue Benchmark
Class of Warrant or Right [Line Items]
Concentration risk								13.00%		14.00%
International | Geographic Concentration Risk | Revenue Benchmark
Class of Warrant or Right [Line Items]
Concentration risk							14.00%	4.00%	12.00%	3.00%
Donald Thompson
Class of Warrant or Right [Line Items]
Consulting fees, related party									$ 0	$ 47,162
Consulting Agreement | Executive Chair
Class of Warrant or Right [Line Items]
Monthly transaction amount	$ 20,210.33
Advisor Agreement | Food System Strategies, LLC
Class of Warrant or Right [Line Items]
Daily transaction amount						$ 4,000
Amended Advisor Agreement | Food System Strategies, LLC
Class of Warrant or Right [Line Items]
Monthly transaction amount				$ 10,000	$ 25,000
Restricted Stock Unit | 2018 Plan | Executive Chair
Class of Warrant or Right [Line Items]
Restricted stock unit fair value			$ 105,000
Vesting period			12 months
Termination period upon prior written notice			120 days
Breach, termination period upon prior written notice, non-breaching party			30 days
Non-qualified Stock Option | Amended Advisor Agreement | Food System Strategies, LLC
Class of Warrant or Right [Line Items]
Vesting period					3 years
Stock options granted (in shares) | shares					798,848
Minimum | Advisor Agreement | Food System Strategies, LLC
Class of Warrant or Right [Line Items]
Days of service						2 days
Minimum | Amended Advisor Agreement | Food System Strategies, LLC
Class of Warrant or Right [Line Items]
Days of service				5 days
Maximum | Amended Advisor Agreement | Food System Strategies, LLC
Class of Warrant or Right [Line Items]
Days of service				6 days