will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents
designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments
by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable
prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with
respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we
initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for
the debt securities of a particular series.
money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities
that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid
to us, and the holder of the debt security thereafter may look only to us for payment thereof.
indenture and the debt securities will be governed by and construed in accordance with the laws of the State of New York, except
to the extent that the Trust Indenture Act is applicable.
debt securities will be unsecured and will be subordinate and junior in priority of payment to certain other indebtedness to the
extent described in a prospectus supplement.
debt securities will be unsecured and will rank equally in right of payment to all our other senior unsecured debt. The indenture
does not limit the amount of senior debt securities that we may issue. It also does not limit us from issuing any other secured
or unsecured debt.
of June 30, 2017, we had $2.0 million in a loan payable to Silicon Valley Bank (which may be increased by $3.0 million subject
to certain conditions), capital lease obligations for equipment amounting to $0.7 million, and an account payable to BioTime of
$2.5 million associated with the BioTime shares we hold as available-for-sale securities. We have no other material existing debt.
may offer warrants for the purchase of shares of common stock or preferred stock or debt securities, in one or more series. We
may issue the warrants by themselves or together with common stock, preferred stock or debt securities, and the warrants may be
attached to or separate from any offered securities. While the terms we have summarized below will apply generally to any warrants
that we may offer under this prospectus, we will describe in particular the terms of any series of warrants that we may offer
in more detail in the applicable prospectus supplement and any applicable free writing prospectus. The terms of any warrants offered
by a prospectus supplement may differ from the terms described below.
will file as an exhibit to the registration statement of which this prospectus forms a part, or will incorporate by reference
from another report that we file with the SEC, the form of warrant or warrant agreement, which may include a form of warrant certificate,
as applicable, that describes the terms of the particular series of warrants we may offer before the issuance of the related series
of warrants. We may issue the warrants under a warrant agreement that we will enter into with a warrant agent to be selected by
us. The warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation or relationship
of agency or trust for or with any registered holders of warrants or beneficial owners of warrants. The following summary of material
provisions of the warrants and warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions
of the form of warrant or warrant agreement and warrant certificate applicable to a particular series of warrants. We urge you
to read the applicable prospectus supplement and any related free writing prospectus, as well as the complete form of warrant
or the warrant agreement and warrant certificate, as applicable, that contain the terms of the warrants.