Common Stock - Outstanding and Reserved Shares of Common Stock for Future Issuance (Detail)	Dec. 31, 2012		Dec. 31, 2011	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2009
Common stock outstanding and reserved shares of common stock for future issuance
Options outstanding	36,115,460		39,601,640	26,326,394	16,520,984	19,164,000
Total reserved shares of common stock for future issuance	53,950,960
2005 Stock Option Plan [Member]
Common stock outstanding and reserved shares of common stock for future issuance
Total reserved shares of common stock for future issuance	0	[1]
2012 Equity Incentive Plan [Member]
Common stock outstanding and reserved shares of common stock for future issuance
Total reserved shares of common stock for future issuance	11,377,630	[1]
2012 Employee Stock Purchase Plan [Member]
Common stock outstanding and reserved shares of common stock for future issuance
Total reserved shares of common stock for future issuance	5,000,000	[1]
Stock Options [Member]
Common stock outstanding and reserved shares of common stock for future issuance
Options outstanding	36,115,460
Restricted Stock Units (RSUs) [Member]
Common stock outstanding and reserved shares of common stock for future issuance
RSUs	1,457,870		0

[1] )Refer to Note 12 for a description of these plan