Debt - Narrative (Details)	1 Months Ended			3 Months Ended								12 Months Ended
	Sep. 29, 2018 USD ($)	Jun. 30, 2018 USD ($)	Nov. 30, 2017 USD ($) purchaser shares	Dec. 31, 2019 USD ($) $ / shares shares	Sep. 28, 2019 USD ($)	Jun. 29, 2019 USD ($)	Mar. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 29, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) shares	May 06, 2019 shares	May 05, 2019 $ / shares shares	Dec. 20, 2013 USD ($)
Debt Instrument [Line Items]
Cost of goods sold				$ 65,018,000	$ 59,178,000	$ 44,510,000	$ 29,435,000	$ 23,651,000	$ 21,235,000	$ 14,755,000	$ 10,719,000	$ 198,141,000	$ 70,360,000	$ 34,772,000
Debt issuance costs				431,000				$ 612,000				431,000	612,000
Amortization of debt issuance costs												181,000	$ 109,000	$ 37,000
Expected term								2 years					2 years	3 years
Right to purchase capital stock				$ 0				$ 1,918,000				$ 0	$ 1,918,000
Warrants outstanding (in shares) | shares				0								0
Line of Credit | SVB Credit Facilities
Debt Instrument [Line Items]
Interest expense												$ 2,200,000	900,000	$ 100,000
Line of Credit | 2018 Revolving Credit Facility
Debt Instrument [Line Items]
Variable annual interest rate, additional upon default		5.00%
Debt, outstanding balance				$ 6,000,000				6,000,000				6,000,000	6,000,000
Current borrowing capacity				$ 0				0				$ 0	0
Interest rate				5.50%								5.50%
Line of Credit | 2018 Term Loan Facility
Debt Instrument [Line Items]
Debt, outstanding balance				$ 20,000,000				20,000,000				$ 20,000,000	20,000,000
Current borrowing capacity				$ 0				0				$ 0	0
Interest rate				8.75%								8.75%
Line of Credit | Equipment Loan Facility
Debt Instrument [Line Items]
Debt, face amount	$ 5,000,000.0								$ 5,000,000.0
Variable annual interest rate	6.25%
Debt, outstanding balance				$ 5,000,000				$ 5,000,000				$ 5,000,000	5,000,000
Interest expense												$ 600,000	$ 200,000	0
Interest rate				11.00%				11.50%				11.00%	11.50%
Stated rate	4.75%								4.75%
Right to purchase capital stock	$ 1,000,000.0								$ 1,000,000.0
Threshold gross proceeds on equity transaction	$ 10,000,000.0
Commitment fee percentage	13.00%
Commitment fee, percent increase	1.00%								1.00%
Promissory Note
Debt Instrument [Line Items]
Debt, face amount																	$ 1,500,000
Interest expense														$ 29,000
Stated rate																	2.00%
Convertible Promissory Note
Debt Instrument [Line Items]
Debt, face amount			$ 10,000,000.0
Stated rate			5.00%
Debt term			6 months
Debt, conversion feature, percent of cash price per share			90.00%
Debt discount			$ 1,100,000
Advance at closing | Line of Credit | 2018 Revolving Credit Facility
Debt Instrument [Line Items]
Debt, face amount		$ 6,000,000.0								6,000,000.0
Advance at closing | Line of Credit | 2018 Term Loan Facility
Debt Instrument [Line Items]
Debt, face amount		$ 10,000,000.0								10,000,000.0
Variable annual interest rate		4.00%
Advance if no event of default | Line of Credit | 2018 Term Loan Facility
Debt Instrument [Line Items]
Debt, face amount		$ 5,000,000.0								5,000,000.0
Advance if no event of default, based on minimum level of gross profit | Line of Credit | 2018 Term Loan Facility
Debt Instrument [Line Items]
Debt, face amount		$ 5,000,000.0								$ 5,000,000.0
Advance upon Structural Capital's approval | Line of Credit | Equipment Loan Facility
Debt Instrument [Line Items]
Debt, face amount	$ 10,000,000.0								$ 10,000,000.0
Debt, additional face amount	$ 5,000,000.0								$ 5,000,000.0
Payments begin six months after loan draw | Line of Credit | Equipment Loan Facility
Debt Instrument [Line Items]
Debt term	37 months
Payments begin 18 months after loan draw | Line of Credit | Equipment Loan Facility
Debt Instrument [Line Items]
Debt term	25 months
First two years | Line of Credit | Equipment Loan Facility
Debt Instrument [Line Items]
Prepayment penalty, percent of facility	2.00%								2.00%
Prepayment penalty, period	2 years
Thereafter | Line of Credit | Equipment Loan Facility
Debt Instrument [Line Items]
Prepayment penalty, percent of facility	1.00%								1.00%
Minimum | Line of Credit | 2018 Revolving Credit Facility
Debt Instrument [Line Items]
Variable annual interest rate		0.75%
Maximum | Line of Credit | 2018 Revolving Credit Facility
Debt Instrument [Line Items]
Variable annual interest rate		1.25%
Common Stock | Line of Credit | SVB Credit Facilities
Debt Instrument [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
Expected term				10 years								10 years
Commitment fee		$ 30,000
Series B
Debt Instrument [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
Debt Instrument [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
Series G
Debt Instrument [Line Items]
Conversion of convertible notes upon issuance of Series G preferred stock(inclusive of $1,123 adjustment upon conversion (in shares) | shares			1,026,367											1,026,367
Series G | Convertible Promissory Note
Debt Instrument [Line Items]
Number of purchasers | purchaser			2
IPO | Common Stock
Debt Instrument [Line Items]
Number of warrants issued (in shares) | shares															160,767
Interest expense
Debt Instrument [Line Items]
Amortization of debt issuance costs												$ 200,000	$ 93,000	$ 37,000
Interest expense | Convertible Promissory Note
Debt Instrument [Line Items]
Debt discount recognized														700,000
Other expense | Convertible Promissory Note
Debt Instrument [Line Items]
Debt discount recognized														$ 400,000
Two Purchasers | Series G
Debt Instrument [Line Items]
Ownership percentage			5.00%