Notes Payable - Summary of Future Minimum Payments Under Loan Agreement (Detail) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Proceeds received on April 1, 2016		$ (2,500)
Total notes payable as of March 31, 2016		12,500
Less current portion of notes payable	[1]		$ (7,834)
Non-current portion of notes payable		11,685
Notes payable [Member]
Debt Instrument [Line Items]
2016		901
2017		4,593
2018		5,842
2019		5,393
2020		2,259
Total minimum payments		18,988
Less amount representing interest		(3,988)
Notes payable, gross		15,000
Unamortized debt discount and issuance costs		$ (815)

[1] The condensed consolidated balance sheet as of December 31, 2015 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015.