Condensed Consolidated Statements of Earnings - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues
Total revenues		$ 126,729	$ 104,695	$ 221,705	$ 190,169
Costs and expenses
Cost of goods sold	[1]	8,386	4,044	12,538	7,728
Research and development		22,247	16,970	41,184	32,364
Selling, general and administrative		48,103	39,777	89,717	79,439
Amortization of intangible assets		2,445	1,306	3,706	2,612
Total costs and expenses		81,181	62,097	147,145	122,143
Operating earnings		45,548	42,598	74,560	68,026
Other income (expense)
Interest income		4,151	5,448	9,726	10,137
Interest expense		(5,815)	(5,389)	(11,570)	(11,268)
Other income, net		3,326	89	3,528	90
Total other income (expense)		1,662	148	1,684	(1,041)
Earnings before income taxes		47,210	42,746	76,244	66,985
Income tax expense		12,543	10,019	20,059	15,918
Net earnings		$ 34,667	$ 32,727	$ 56,185	$ 51,067
Earnings per share
Basic (in dollars per share)		$ 0.66	$ 0.62	$ 1.07	$ 0.98
Diluted (in dollars per share)		$ 0.65	$ 0.61	$ 1.05	$ 0.95
Weighted-average shares outstanding
Basic (in shares)		52,557,035	52,385,590	52,545,910	52,361,149
Diluted (in shares)		53,645,828	53,912,977	53,611,418	53,947,834
Net product sales
Revenues
Total revenues		$ 123,984	$ 102,358	$ 216,474	$ 185,457
Royalty revenues
Revenues
Total revenues		$ 2,745	$ 2,337	$ 5,231	$ 4,712

[1] Excludes amortization of acquired intangible assets