Stockholder's Equity - Shares of Common Stock Issuable on Conversion or Exercise of Rights Granted Under Prior Financing Arrangements, Stock Options and Warrants (Detail)	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for future issuances	16,344,028
Series E convertible voting preferred stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for future issuances	40,000
Antidilutive options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for future issuances	10,932,574
Exercise of warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for future issuances	445,000
Employee stock purchase plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for future issuances	4,579,954
Long-term retention and management incentive plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares of common stock reserved for future issuances	346,500