Summary of Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Net sales	$ 23,210	$ 22,412	$ 20,525	$ 17,552	$ 19,021	$ 16,875	$ 17,554	$ 14,676	$ 83,699	$ 68,126	$ 36,542
Gross profit	14,239	12,658	12,712	11,078	11,354	10,477	10,894	8,579	50,687	41,304	22,371
Net loss	$ (20,247)	$ (22,433)	$ (37,654)	$ (26,484)	$ (24,631)	$ (20,545)	$ (18,028)	$ (19,423)	$ (106,818)	$ (82,627)	$ (64,028)
Net loss per share:
Basic and diluted	$ (0.41)	$ (0.45)	$ (1.10)	$ (0.91)	$ (0.86)	$ (0.72)	$ (0.73)	$ (0.99)	$ (2.63)	$ (3.25)	$ (3.34)