Segments - Revenues, Expenses and Operating Income (Loss) by Market Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Total revenues	$ 2,321	$ 3,038	$ 4,539	$ 5,671
Operating expenses:
Total operating expenses	3,262	3,405	6,969	7,222
Operating income (loss):
Total operating income (loss)	(941)	(367)	(2,430)	(1,551)
Anti-aging Cosmetic Market [Member]
Revenues:
Total revenues	471	388	900	885
Operating expenses:
Total operating expenses	717	637	1,319	1,342
Operating income (loss):
Total operating income (loss)	(246)	(249)	(419)	(457)
Biomedical Market [Member]
Revenues:
Total revenues	1,850	2,650	3,639	4,786
Operating expenses:
Total operating expenses	1,404	1,537	2,850	2,834
Operating income (loss):
Total operating income (loss)	446	1,113	789	1,952
Therapeutic Market [Member]
Operating expenses:
Total operating expenses	1,141	1,231	2,800	3,046
Operating income (loss):
Total operating income (loss)	$ (1,141)	$ (1,231)	$ (2,800)	$ (3,046)