Recognition of Share-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share based Compensation Arrangement by Share-based Payment Award [Line Items]
Research and development	$ 1,281	$ 805	$ 2,719	$ 2,831
Share based Compensation Expense recognized in Operations	289	315	487	630
Stock options
Share based Compensation Arrangement by Share-based Payment Award [Line Items]
Research and development	56	81	113	162
General and administrative	141	234	282	468
Share based Compensation Expense recognized in Operations	197	315	395	630
Restricted Stock Units (RSUs)
Share based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative	$ 92	$ 0	$ 92	$ 0

- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

+ References+ Details