Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 98,479	$ 91,961	$ 67,251	$ 40,206	$ 31,514	$ 26,277	$ 17,367	$ 12,776	$ 297,897	$ 87,934	$ 32,581
Cost of goods sold	65,018	59,178	44,510	29,435	23,651	21,235	14,755	10,719	198,141	70,360	34,772
Gross profit (loss)	$ 33,461	$ 32,783	$ 22,741	$ 10,771	$ 7,863	$ 5,042	$ 2,612	$ 2,057	99,756	17,574	(2,191)
Gross margin	34.00%	35.60%	33.80%	26.80%	25.00%	19.20%	15.00%	16.10%
Research and development expenses	$ 5,989	$ 5,951	$ 4,212	$ 4,498	$ 3,320	$ 2,165	$ 2,497	$ 1,605	20,650	9,587	5,722
Selling, general and administrative expenses	27,090	20,944	15,515	11,177	11,328	10,353	7,043	5,737	74,726	34,461	17,143
Restructuring expenses	1,309	2,319	847	394	345	528	348	294	4,869	1,515	3,509
Total operating expenses	34,388	29,214	20,574	16,069	14,993	13,046	9,888	7,636	100,245	45,563	26,374
Loss from operations	(927)	3,569	2,167	(5,298)	(7,130)	(8,004)	(7,276)	(5,579)	(489)	(27,989)	(28,565)
Other (expense) income:
Interest expense	(742)	(855)	(741)	(733)	(740)	(313)	(28)	(47)	(3,071)	(1,128)	(1,002)
Remeasurement of warrant liability	0	0	(11,744)	(759)	133	(994)	(130)	(129)	(12,503)	(1,120)	(385)
Other, net	1,205	1,385	898	141	286	(31)	38	59	3,629	352	(427)
Total other expense, net	463	530	(11,587)	(1,351)	(321)	(1,338)	(120)	(117)	(11,945)	(1,896)	(1,814)
Loss before taxes	(464)	4,099	(9,420)	(6,649)	(7,451)	(9,342)	(7,396)	(5,696)	(12,434)	(29,885)	(30,379)
Income tax expense	(12)	0	21	0	1	0	0	0	9	1	5
Net loss	$ (452)	$ 4,099	$ (9,441)	$ (6,649)	$ (7,452)	$ (9,342)	$ (7,396)	$ (5,696)	$ (12,443)	$ (29,886)	$ (30,384)
Net (loss) income per share available to common stockholders:
Basic (in dollars per share)	$ (0.01)	$ 0.07	$ (0.24)	$ (0.95)	$ (1.10)	$ (1.45)	$ (1.22)	$ (0.98)
Diluted (in dollars per share)	$ (0.01)	$ 0.06	$ (0.24)	$ (0.95)	$ (1.10)	$ (1.45)	$ (1.22)	$ (0.98)