XML 41 R31.htm IDEA: XBRL DOCUMENT

Major Customers, Partnerships and Strategic Alliances - California Institute for Regenerative Medicine - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2014	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research grants		$ 53,000	$ 95,000	$ 448,000	$ 436,000
California Institute for Regenerative Medicine [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Funds due under the agreement	$ 5,600,000
Agreement to receive	4 years
Research grants		0	0	0	0
Collaboration agreement related costs and expenses		$ 500,000	$ 600,000	$ 800,000	$ 1,200,000