Security	Date	Code	Shares	Price	A/D	Owned after	D/I
Common Stock^F8,F1,F2	May 26, 2016	S	24,103	$13.508	D	2,432,922	D
Common Stock^F8,F3,F4	May 26, 2016	S	897	$13.508	D	90,491	D
Common Stock^F9,F2,F5	May 27, 2016	S	20,811	$13.462	D	2,412,111	D
Common Stock^F9,F4,F6	May 27, 2016	S	775	$13.462	D	89,716	D
Common Stock^F7	holding	—	—		—	10,000	D

Table II — derivative securities

No Table II lines on this filing.

Explanation of responses

F1On May 26, 2016, General Catalyst Group II, L.P. ("GCG II") sold a total of 24,103 shares of Common Stock of the Issuer. The remaining shares are held by GCG II.
F2General Catalyst GP II, LLC ("GC II LLC") is the general partner of General Catalyst Partners II, L.P. ("GC II LP"), which is the general partner of GCG II. Each of GC II LLC and GC II LP disclaims beneficial ownership of the shares and this report shall not be deemed an admission that such reporting person is the beneficial owner of such shares, except to the extent of its pecuniary interest, if any, in the shares. Each of Joel Cutler, David Fialkow and David Orfao is a managing director of GC II LLC and may be deemed to share voting and dispositive power of the shares held by GCG II. Each of the managing directors disclaims beneficial ownership of such shares and this report shall not be deemed an admission that such reporting person is the beneficial owner of such shares, except to the extent of his pecuniary interest, if any, in the shares.
F3On May 26, 2016, GC Entrepreneurs Fund II, L.P. ("GC EF II") sold a total of 897 shares of Common Stock of the Issuer. The remaining shares are held by GC EF II.
F4GC II LLC is the general partner of GC II LP, which is the general partner of GC EF II. Each of GC II LLC and GC II LP disclaims beneficial ownership of the shares and this report shall not be deemed an admission that such reporting person is the beneficial owner of such shares, except to the extent of its pecuniary interest, if any, in the shares. Each of Joel Cutler, David Fialkow and David Orfao is a managing director of GC II LLC and may be deemed to share voting and dispositive power of the shares held by GC EF II. Each of the managing directors disclaims beneficial ownership of such shares and this report shall not be deemed an admission that such reporting person is the beneficial owner of such shares, except to the extent of his pecuniary interest, if any, in the shares
F5On May 27, 2016, GCG II sold a total of 20,811 shares of Common Stock of the Issuer. The remaining securities are held by GCG II.
F6On May 27, 2016, GC EF II sold a total of 775 shares of Common Stock of the Issuer. The remaining securities are held by GC EF II.
F7Shares held directly by David Orfao. None of the other reporting persons has a pecuniary interest in or beneficial ownership of such shares.
F8The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.46 to $13.71, inclusive. The reporting person undertakes to provide to IMPR, any security holder of IMPR, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (8) and (9) to this Form 4.
F9The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.40 to $13.63, inclusive.