Major Customers, Partnerships and Strategic Alliances - Agreement with Sigma-Aldrich Corporation - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Oct. 31, 2009	Jul. 31, 2007	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development			$ 15,618	$ 13,460	$ 30,598	$ 25,543
Sigma-Aldrich Corporation [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research program to develop laboratory research reagents		3 years
Upfront license fee	$ 20,000
Public offering, common stock shares issued	636,133
Amount received on commercial license fees					$ 5,000
Reduced royalty rate					10.50%
Funding available under the amended agreement			25,000		$ 25,000
Sigma-Aldrich Corporation [Member] | Upfront license fee [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront license fee	$ 15,100
Common stock issued under license agreement	4,900
Sigma-Aldrich Corporation [Member] | License agreement terms [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenues expected to be received	$ 5,000
Research and development			$ 100	$ 100	$ 300	$ 100