Customer Concentration (Percentage of Total Revenue From Licenses Over 10% of Revenue) (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AcelRx [Member]
Concentration Risk [Line Items]
Royalty by Licensee as a percentage of revenue, Percentage	(104.00%)	(1.00%)	2.00%
Biogen Idec [Member]
Concentration Risk [Line Items]
Royalty by Licensee as a percentage of revenue, Percentage	0.00%	2.00%	11.00%
Depomed [Member]
Concentration Risk [Line Items]
Royalty by Licensee as a percentage of revenue, Percentage	48.00%	42.00%	52.00%
LENSAR [Member]
Concentration Risk [Line Items]
Royalty by Licensee as a percentage of revenue, Percentage	56.00%	12.00%	5.00%
Noden [Member]
Concentration Risk [Line Items]
Royalty by Licensee as a percentage of revenue, Percentage	101.00%	41.00%	22.00%