CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
Net sales	$ 58,509,000	$ 43,908,000	$ 171,135,000	$ 127,202,000
Cost of sales	7,703,000	6,011,000	22,684,000	17,957,000
Gross profit	50,806,000	37,897,000	148,451,000	109,245,000
Operating expenses:
Selling, general and administrative	44,443,000	31,632,000	117,024,000	87,425,000
Research and development	17,278,000	13,202,000	48,277,000	36,719,000
In-process research and development (Note 1)	1,500,000		3,745,000
Total operating expenses	63,221,000	44,834,000	169,046,000	124,144,000
Loss from operations	(12,415,000)	(6,937,000)	(20,595,000)	(14,899,000)
Non-operating income (expense):
Interest income	780,000	583,000	2,368,000	1,568,000
Interest expense	(1,028,000)		(2,041,000)
Other expense, net	(656,000)	(230,000)	(508,000)	(1,346,000)
Total non-operating (expense) income	(904,000)	353,000	(181,000)	222,000
Loss before taxes	(13,319,000)	(6,584,000)	(20,776,000)	(14,677,000)
Provision for income taxes	187,000	37,000	381,000	53,000
Net loss	$ (13,506,000)	$ (6,621,000)	$ (21,157,000)	$ (14,730,000)
Basic and diluted net loss per share (in dollar per share)	$ (0.37)	$ (0.19)	$ (0.58)	$ (0.42)
Weighted-average shares used to compute basic and diluted net loss per share	36,831	35,541	36,507	35,075