Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
4.00% Convertible Secured Subordinated Notes^F1	$5.00	Dec 17, 2015	P	—	A	Dec 17, 2015	Apr 15, 2018	Common Stock	155,734	—	I
4.00% Convertible Secured Subordinated Notes^F2	$5.00	Dec 17, 2015	P	—	A	Dec 17, 2015	Apr 15, 2018	Common Stock	18,960	—	I
4.00% Convertible Secured Subordinated Notes^F3	$5.00	Dec 17, 2015	P	—	A	Dec 17, 2015	Apr 15, 2018	Common Stock	673,946	—	I
4.00% Convertible Secured Subordinated Notes^F4	$5.00	Dec 17, 2015	P	—	A	Dec 17, 2015	Apr 15, 2018	Common Stock	2,455	—	I
4.00% Convertible Secured Subordinated Notes^F5	$5.00	Dec 17, 2015	P	—	A	Dec 17, 2015	Apr 15, 2018	Common Stock	81,433	—	I
4.00% Convertible Secured Subordinated Notes^F6	$5.00	Dec 17, 2015	P	—	A	Dec 17, 2015	Apr 15, 2018	Common Stock	67,469	—	I

Explanation of responses

F1These securities are directly held by VantagePoint Venture Partners III (Q), L.P.. VantagePoint Venture Associates III, L.L.C. is the general partner of VantagePoint Venture Partners III (Q), L.P.. VantagePoint Venture Associates III, L.L.C. disclaims beneficial ownership of such securities except to the extent of its pecuniary interest in such securities. Alan E. Salzman, a managing member of VantagePoint Venture Associates III, L.L.C., disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.
F2These securities are directly held by VantagePoint Venture Partners III, L.P.. VantagePoint Venture Associates III, L.L.C. is the general partner of VantagePoint Venture Partners III, L.P.. VantagePoint Venture Associates III, L.L.C. disclaims beneficial ownership of such securities except to the extent of its pecuniary interest in such securities. Alan E. Salzman, a managing member of VantagePoint Venture Associates III, L.L.C., disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.
F3These securities are directly held by VantagePoint Venture Partners IV(Q), L.P.. VantagePoint Venture Associates IV, L.L.C. is the general partner of VantagePoint Venture Partners IV(Q), L.P.. VantagePoint Venture Associates IV, L.L.C. disclaims beneficial ownership of such securities except to the extent of its pecuniary interest in such securities. Alan E. Salzman, a managing member of VantagePoint Venture Associates IV, L.L.C., disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.
F4These securities are directly held by VantagePoint Venture Partners IV Principals Fund, L.P.. VantagePoint Venture Associates IV, L.L.C. is the general partner of VantagePoint Venture Partners IV Principals Fund, L.P.. VantagePoint Venture Associates IV, L.L.C. disclaims beneficial ownership of such securities except to the extent of its pecuniary interest in such securities. Alan E. Salzman, a managing member of VantagePoint Venture Associates IV, L.L.C., disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.
F5These securities are directly held by VantagePoint Venture Partners 2006(Q), L.P.. VantagePoint Venture Associates 2006, L.L.C. is the general partner of VantagePoint Venture Partners 2006(Q), L.P.. VantagePoint Venture Associates 2006, L.L.C. disclaims beneficial ownership of such securities except to the extent of its pecuniary interest in such securities. Alan E. Salzman, a managing member of VantagePoint Venture Associates 2006, L.L.C., disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.
F6These securities are directly held by VantagePoint Venture Partners IV, L.P.. VantagePoint Venture Associates IV, L.L.C. is the general partner of VantagePoint Venture Partners IV, L.P.. VantagePoint Venture Associates IV, L.L.C. disclaims beneficial ownership of such securities except to the extent of its pecuniary interest in such securities. Alan E. Salzman, a managing member of VantagePoint Venture Associates IV, L.L.C., disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.