Note 10 - Subsequent Events	3 Months Ended
Mar. 31, 2018
Notes to Financial Statements
Subsequent Events [Text Block]	10 . Subsequent Events In April 2018, we sold 6.9 million shares of our common stock at a public offering price of $26.00 per share. We received total net cash proceeds of $168.7 million (net of $9.3 million in issuance costs) from the sale of the common stock. In connection with the public offering, TCP executed a waiver (the “Waiver”) pursuant to which TCP waived: (i) our obligation under the Securities Purchase Agreement, dated April 24, 2011, among us, TCP and certain other investors to maintain a sufficient number of authorized shares of our common stock to permit the conversion of TCP’s outstanding principal and interest under the Convertible Notes to our common stock; and (ii) its right to convert the Convertible Notes for the duration of the Waiver. The Waiver will remain effective until the earliest to occur of: (i) a change in the control of the Company; (ii) the Company’s stockholders approving an increase of the number of authorized shares of our common stock; and (iii) September 28, 2018. If, upon the expiration of the Waiver, TCP seeks to convert part or all of the Convertible Notes and we do not have a sufficient number of authorized shares of our common stock to permit the conversion of the portion of the Convertible Notes being converted, then we will be obligated to make a cash payment to TCP equal to the value of the underlying shares of common stock that we are unable to deliver on conversion based on the price of our common stock at such time. On May 8, 2018, we entered into a Second Amendment to Lease (the “Lease Amendment”) with AP3 - SD1 Campus Point LLC (the “Landlord”), amending that certain Lease, dated October 18, 2016, by and between us and the Landlord, as amended by that certain First Amendment to Lease, dated March 15, 2017 ( the “Lease”). The Lease Amendment provides for us to lease additional office space in the building located at 4242 Campus Point Court, San Diego, California, for a period of 87 months, beginning on the date that our improvements to the premises are substantially complete. Pursuant to the Lease Amendment, we have agreed to pay a basic annual rent that increases incrementally over the term of the Lease Amendment from $0.9 million for the first 12 months of the Lease Amendment (inclusive of certain rent abatements) to a prorated portion of a basic annual rent of $1.4 million for the last three months of the Lease Amendment, and such other amounts as set forth in the Lease Amendment. We also paid to the Landlord an additional security deposit in the amount of $0.1 million. Except as modified by the Lease Amendment, all of the provisions of the Lease will continue unmodified and in full force and effect.

Subsequent Events

April 2018,

we sold

6.9

million shares of our common stock at a public offering price of

$26.00

per share. We received total net cash proceeds of

$168.7

million (net of

$9.3

million in issuance costs) from the sale of the common stock.

In connection with the public offering, TCP executed a waiver (the “Waiver”) pursuant to which TCP waived: (i) our obligation under the Securities Purchase Agreement, dated

April

24,

2011,

among us, TCP and certain other investors to maintain a sufficient number of authorized shares of our common stock to permit the conversion of TCP’s outstanding principal and interest under the Convertible Notes to our common stock; and (ii) its right to convert the Convertible Notes for the duration of the Waiver. The Waiver will remain effective until the earliest to occur of: (i) a change in the control of the Company; (ii) the Company’s stockholders approving an increase of the number of authorized shares of our common stock; and (iii)

September 28, 2018.

If, upon the expiration of the Waiver, TCP seeks to convert part or all of the Convertible Notes and we do

not

have a sufficient number of authorized shares of our common stock to permit the conversion of the portion of the Convertible Notes being converted, then we will be obligated to make a cash payment to TCP equal to the value of the underlying shares of common stock that we are unable to deliver on conversion based on the price of our common stock at such time.

May 8, 2018,

we entered into a Second Amendment to Lease (the “Lease Amendment”) with

AP3

SD1

Campus Point LLC (the “Landlord”), amending that certain Lease, dated

October 18, 2016,

by and between us and the Landlord, as amended by that certain First Amendment to Lease, dated

March 15, 2017 (

the “Lease”). The Lease Amendment provides for us to lease additional office space in the building located at

4242

Campus Point Court, San Diego, California, for a period of

months, beginning on the date that our improvements to the premises are substantially complete. Pursuant to the Lease Amendment, we have agreed to pay a basic annual rent that increases incrementally over the term of the Lease Amendment from

$0.9

million for the

first

months of the Lease Amendment (inclusive of certain rent abatements) to a prorated portion of a basic annual rent of

$1.4

million for the last

three

months of the Lease Amendment, and such other amounts as set forth in the Lease Amendment. We also paid to the Landlord an additional security deposit in the amount of

$0.1

million. Except as modified by the Lease Amendment, all of the provisions of the Lease will continue unmodified and in full force and effect.