Significant Components of Deferred Tax Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Federal and state net operating losses	$ 55,955	$ 45,954
Capitalized research and patent costs	23,395	22,442
Research credits	21,252	19,236
Biopharma Financing Agreement	13,021	12,108
Stock-based compensation costs	5,398	4,320
Other	1,148	189
Total deferred tax assets	120,169	104,249
Valuation allowance	(120,169)	(104,249)
Net deferred tax assets