The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
Estimated average burden
hours per response: 23.8
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
3-D SYS CORP DEL COM NEW COM 88554D205 1,032 95,902 SH   SOLE   95,902 0 0
3M COMPANY COM 88579y101 1,391 6,693 SH   SOLE   6,693 0 0
A. O. SMITH CORPORATION COM 831865209 10,233 191,926 SH   SOLE   191,926 0 0
AAC HOLDINGS INC COM 000307108 297 161,485 SH   SOLE   161,485 0 0
ABBOTT LABORATORIES COM 002824100 1,010 12,638 SH   SOLE   12,638 0 0
ABBVIE INC SHS COM 00287y109 630 7,822 SH   SOLE   7,822 0 0
ACTIVISION BLIZZARD INC COM 00507v109 2,479 54,453 SH   SOLE   54,453 0 0
AIR PRODUCTS & CHEMICALS, INC. COM 009158106 412 2,158 SH   SOLE   2,158 0 0
ALLEGION PLC COM G0176J109 2,396 26,412 SH   SOLE   26,412 0 0
ALLSTATE CORPORATION COM 020002101 2,772 29,433 SH   SOLE   29,433 0 0
ALPHABET INC CLASS C COM 02079K107 109,076 92,964 SH   SOLE   92,964 0 0
ALPHABET INC. CLASS A COM 02079k305 1,492 1,268 SH   SOLE   1,268 0 0
ALTRIA GROUP INC COM 02209s103 256 4,450 SH   SOLE   4,450 0 0
AMAZON.COM INC COM 023135106 118,336 66,453 SH   SOLE   66,453 0 0
AMERICAN TOWER CORP. COM 03027X100 122,956 623,953 SH   SOLE   623,953 0 0
AMGEN INC COM PV $0.0001 COM 031162100 980 5,156 SH   SOLE   5,156 0 0
ANSYS INC COM 03662Q105 178,553 977,248 SH   SOLE   977,248 0 0
APPLE INC COM 037833100 6,030 31,745 SH   SOLE   31,745 0 0
AUTOMATIC DATA PROC COM 053015103 2,149 13,456 SH   SOLE   13,456 0 0
BANK AMER CORP COM COM 060505104 284 10,311 SH   SOLE   10,311 0 0
BANK OF HAWAII CORP COM 062540109 232 2,942 SH   SOLE   2,942 0 0
BB&T CORPORATION COM 054937107 544 11,700 SH   SOLE   11,700 0 0
BEACON ROOFING SUPPLY INC COM 073685109 5,488 170,654 SH   SOLE   170,654 0 0
BECTON DICKINSON&CO COM 075887109 368 1,475 SH   SOLE   1,475 0 0
BERKLEY W R CORP COM 084423102 2,933 34,625 SH   SOLE   34,625 0 0
BERKSHIRE HATHAWAY INC DELAWA COM 084670108 2,711 9 SH   SOLE   9 0 0
BERKSHIRE HATHAWAY INC CL B COM 084670702 8,369 41,662 SH   SOLE   41,662 0 0
BIO-TECHNE CORP COM 09073M104 118,922 598,951 SH   SOLE   598,951 0 0
BLACK KNIGHT, INC. COM 09215C105 62,402 1,144,986 SH   SOLE   1,144,986 0 0
BLACKBAUD INC COM 09227Q100 45,968 576,540 SH   SOLE   576,540 0 0
BLACKLINE, INC. COM 09239B109 135,322 2,921,452 SH   SOLE   2,921,452 0 0
BRIGHT HORIZONS FAM SOL IN DEL COM 109194100 6,935 54,562 SH   SOLE   54,562 0 0
BRITISH AMER TOBACCO PLC ADR COM 110448107 225 5,402 SH   SOLE   5,402 0 0
BROOKS AUTOMATION, INC. COM 114340102 78,887 2,689,641 SH   SOLE   2,689,641 0 0
CALAVO GROWERS INC COM 128246105 5,060 60,347 SH   SOLE   60,347 0 0
CANADIAN NATL RY CO COM COM 136375102 1,804 20,160 SH   SOLE   20,160 0 0
CANTEL MEDICAL CORP COM 138098108 3,263 48,786 SH   SOLE   48,786 0 0
CAPITAL ONE FINL CORP COM COM 14040H105 2,230 27,296 SH   SOLE   27,296 0 0
CARMAX INC COM 143130102 134,859 1,932,073 SH   SOLE   1,932,073 0 0
CBRE GROUP INC COM 12504L109 80,322 1,624,316 SH   SOLE   1,624,316 0 0
CELGENE CORP COM 151020104 11,352 120,334 SH   SOLE   120,334 0 0
CHEVRON CORP COM 166764100 1,288 10,453 SH   SOLE   10,453 0 0
CHUBB LTD COM h1467j104 784 5,600 SH   SOLE   5,600 0 0
CHURCH & DWIGHT INC COM COM 171340102 1,800 25,268 SH   SOLE   25,268 0 0
CIGNA CORP COM 125523100 327 2,036 SH   SOLE   2,036 0 0
CISCO SYSTEMS INC COM COM 17275r102 3,337 61,802 SH   SOLE   61,802 0 0
COCA COLA COM COM 191216100 1,809 38,613 SH   SOLE   38,613 0 0
COGENT COMMUNICATIONS COM 19239V302 8,486 156,418 SH   SOLE   156,418 0 0
COLGATE-PALMOLIVE CO COM 194162103 831 12,125 SH   SOLE   12,125 0 0
COMCAST CORP NEW CL A COM 20030n101 5,502 137,608 SH   SOLE   137,608 0 0
CONOCOPHILLIPS COM 20825c104 629 9,420 SH   SOLE   9,420 0 0
CONSOLIDATED EDISON INC COM COM 209115104 216 2,544 SH   SOLE   2,544 0 0
CONSTELLATION SOFTWARE INC. COM 21037x100 6,841 8,088 SH   SOLE   8,088 0 0
CORE LAB N.V. COM N22717107 21,948 318,412 SH   SOLE   318,412 0 0
COSTAR GROUP INC COM 22160N109 115,596 247,837 SH   SOLE   247,837 0 0
COUPA SOFTWARE COM 22266l106 2,204 24,228 SH   SOLE   24,228 0 0
CROWN CASTLE REIT INC SHS COM 22822v101 7,452 58,216 SH   SOLE   58,216 0 0
CVS HEALTH CORP COM 126650100 202 3,740 SH   SOLE   3,740 0 0
DANAHER CORP DEL COM COM 235851102 56,440 427,512 SH   SOLE   427,512 0 0
DELTA AIR LINES INC COM 247361702 207 4,000 SH   SOLE   4,000 0 0
DEXCOM INC COM 252131107 4,955 41,600 SH   SOLE   41,600 0 0
DISCOVER FINANCIAL SERVICES COM 254709108 5,048 70,938 SH   SOLE   70,938 0 0
DISNEY (WALT) CO COM STK COM 254687106 579 5,212 SH   SOLE   5,212 0 0
DOLLAR GENERAL COM 256677105 5,557 46,577 SH   SOLE   46,577 0 0
DOUGLAS DYNAMICS INC COM 25960R105 7,399 194,357 SH   SOLE   194,357 0 0
DOWDUPONT INC COM 26078j100 316 5,920 SH   SOLE   5,920 0 0
DUKE REALTY CORP REIT COM 264411505 342 11,175 SH   SOLE   11,175 0 0
EAST WEST BANCORP INC COM 27579r104 360 7,500 SH   SOLE   7,500 0 0
ECOLAB INC COM 278865100 211,365 1,197,267 SH   SOLE   1,197,267 0 0
EDWARDS LIFESCIENCES COM 28176e108 2,506 13,096 SH   SOLE   13,096 0 0
ELI LILLY & CO COM 532457108 943 7,264 SH   SOLE   7,264 0 0
ELLIE MAE INC COM 28849P100 656 6,648 SH   SOLE   6,648 0 0
EMERSON ELECTRIC CO COM 291011104 748 10,926 SH   SOLE   10,926 0 0
ENPHASE ENERGY INC COM 29355A107 148 16,000 SH   SOLE   16,000 0 0
ENTERPRISE PRDTS PRTN LPL P COM 293792107 1,269 43,617 SH   SOLE   43,617 0 0
ENVESTNET INC COM 29404K106 77,336 1,182,696 SH   SOLE   1,182,696 0 0
EQUITY RESIDENTIAL REIT COM 29476l107 289 3,838 SH   SOLE   3,838 0 0
EVENTBRITE INC COM 29975e109 3,097 161,538 SH   SOLE   161,538 0 0
EVERTEC INC COM 30040P103 3,075 110,566 SH   SOLE   110,566 0 0
EVO PAYMENT INC COM 26927e104 5,740 197,578 SH   SOLE   197,578 0 0
EXACT SCIENCES CORP COM COM 30063p105 260 3,000 SH   SOLE   3,000 0 0
EXPONENT INC COM 30214U102 3,158 54,713 SH   SOLE   54,713 0 0
EXXON MOBIL CORP COM COM 30231g102 2,140 26,487 SH   SOLE   26,487 0 0
FACEBOOK INC CLASS COM 30303m102 264 1,582 SH   SOLE   1,582 0 0
FASTENAL CO COM 311900104 142,461 2,215,218 SH   SOLE   2,215,218 0 0
FISERV INC COM 337738108 11,982 135,724 SH   SOLE   135,724 0 0
FORTINET INC COM COM 34959E109 862 10,263 SH   SOLE   10,263 0 0
FORTIVE CORPORATION COM 34959J108 210 2,508 SH   SOLE   2,508 0 0
GENERAL ELECTRIC COM 369604103 522 52,229 SH   SOLE   52,229 0 0
GENESEE AND WYOMING INC COM 371559105 58,396 670,140 SH   SOLE   670,140 0 0
GENUINE PARTS CO COM 372460105 362 3,229 SH   SOLE   3,229 0 0
GLU MOBILE INC COM 379890106 137 12,500 SH   SOLE   12,500 0 0
GUIDEWIRE SOFTWARE INC COM 40171V100 7,052 72,579 SH   SOLE   72,579 0 0
HAMILTON LANE INC COM 407497106 5,666 130,018 SH   SOLE   130,018 0 0
HCP INC COM 40414l109 1,478 47,211 SH   SOLE   47,211 0 0
HD SUPPLY HOLDINGS INC COM 40416M105 2,615 60,321 SH   SOLE   60,321 0 0
HEALTHCARE SERVICES GROUP INC COM 421906108 80,034 2,426,010 SH   SOLE   2,426,010 0 0
HEICO CORP NEW CL A COM 422806208 10,251 121,948 SH   SOLE   121,948 0 0
HELIOS TECHNOLOGIES, INC. COM 866942105 4,283 92,093 SH   SOLE   92,093 0 0
HOME DEPOT INC COM 437076102 515 2,684 SH   SOLE   2,684 0 0
HONEYWELL INTL INC COM 438516106 3,390 21,332 SH   SOLE   21,332 0 0
IBM CORP COM 459200101 1,332 9,440 SH   SOLE   9,440 0 0
IDEXX LABORATORIES INC COM 45168D104 24,819 110,996 SH   SOLE   110,996 0 0
ILLINOIS TOOL WORKS COM 452308109 298 2,074 SH   SOLE   2,074 0 0
ILLUMINA INC COM 452327109 130,476 419,954 SH   SOLE   419,954 0 0
INTEL CORP COM 458140100 15,400 286,784 SH   SOLE   286,784 0 0
INTERCONTINENTAL EXCHANGE INC COM 45866F104 2,037 26,758 SH   SOLE   26,758 0 0
INTUITIVE SURGICAL INC COM 46120E602 129,668 227,257 SH   SOLE   227,257 0 0
JOHN BEAN TECHNOLOGIES COM 477839104 6,651 72,384 SH   SOLE   72,384 0 0
JOHNSON AND JOHNSON COM COM 478160104 14,772 105,673 SH   SOLE   105,673 0 0
JPMORGAN CHASE & CO COM 46625h100 2,106 20,803 SH   SOLE   20,803 0 0
KANSAS CITY SOUTHERN COM NEW COM 485170302 2,712 23,383 SH   SOLE   23,383 0 0
KEYON COMMUNI HOLD INC COM 493312201 0 16,667 SH   SOLE   16,667 0 0
KEYSIGHT TECHNOLOGIES INC COM 49338l103 2,394 27,456 SH   SOLE   27,456 0 0
KIMBERLY CLARK COM 494368103 336 2,713 SH   SOLE   2,713 0 0
LABORATORY CORP AMER HLDGS COM COM 50540R409 2,323 15,187 SH   SOLE   15,187 0 0
LEMAITRE VASCULAR COM 525558201 2,460 79,340 SH   SOLE   79,340 0 0
LINCOLN NTL CORP IND NPV COM 534187109 622 10,603 SH   SOLE   10,603 0 0
LITHIA MOTORS INC CL A COM 536797103 2,481 26,750 SH   SOLE   26,750 0 0
LITTELFUSE INC COM 537008104 2,339 12,820 SH   SOLE   12,820 0 0
LKQ CORP COM 501889208 6,820 240,311 SH   SOLE   240,311 0 0
LOWE'S COMPANIES INC COM 548661107 4,124 37,668 SH   SOLE   37,668 0 0
M & T BANK CORP COM 55261f104 507 3,227 SH   SOLE   3,227 0 0
MAGELLAN MIDSTREAM PRTNRS LP C COM 559080106 373 6,150 SH   SOLE   6,150 0 0
MARKEL CORP HLDG CO COM 570535104 127,061 127,541 SH   SOLE   127,541 0 0
MASTERCARD INC-CLASS A COM 57636Q104 108,436 460,549 SH   SOLE   460,549 0 0
MCCORMICK & CO INC COM NON VTG COM 579780206 1,846 12,255 SH   SOLE   12,255 0 0
MCDONALDS CORP COM COM 580135101 576 3,035 SH   SOLE   3,035 0 0
MERCK AND CO INC SHS COM 58933y105 4,315 51,882 SH   SOLE   51,882 0 0
MESA LABS INC COM 59064R109 5,938 25,761 SH   SOLE   25,761 0 0
MGP INGREDIENTS INC COM 55303J106 3,001 38,894 SH   SOLE   38,894 0 0
MICROSOFT CORP COM 594918104 12,702 107,701 SH   SOLE   107,701 0 0
MIDDLEBY CORP COM 596278101 6,581 50,608 SH   SOLE   50,608 0 0
MONRO INC COM 610236101 5,742 66,366 SH   SOLE   66,366 0 0
MOODYS CORP COM 615369105 147,685 815,536 SH   SOLE   815,536 0 0
NASPERS SPON ADR EACH REP 0.2 COM 631512209 313 6,750 SH   SOLE   6,750 0 0
NEOGEN CORP COM COM 640491106 712 12,400 SH   SOLE   12,400 0 0
NESTLE S A REP RG SH ADR COM 641069406 566 5,942 SH   SOLE   5,942 0 0
NORFOLK SOUTHERN CO COM 655844108 3,431 18,358 SH   SOLE   18,358 0 0
NOVANTA INC COM NPV COM 67000b104 7,115 83,968 SH   SOLE   83,968 0 0
NOVARTIS ADR COM 66987v109 508 5,285 SH   SOLE   5,285 0 0
NUTRIEN LTD COM 67077m108 1,682 31,875 SH   SOLE   31,875 0 0
O REILLY AUTOMOTIVE INC COM 67103H107 19,373 49,892 SH   SOLE   49,892 0 0
OKTA, INC. COM 679295105 51,551 623,129 SH   SOLE   623,129 0 0
ORACLE CORPORATION COM 68389x105 216 4,025 SH   SOLE   4,025 0 0
ORTHOPEDIATRICS CORP COM 68752L100 11,961 270,432 SH   SOLE   270,432 0 0
PAYCHEX INC COM 704326107 3,836 47,830 SH   SOLE   47,830 0 0
PEPSICO INC COM 713448108 1,489 12,152 SH   SOLE   12,152 0 0
PFIZER INC COM 717081103 3,071 72,309 SH   SOLE   72,309 0 0
PHILIP MORRIS INTL COM 718172109 251 2,842 SH   SOLE   2,842 0 0
PHILLIPS 66 COM 718546104 207 2,170 SH   SOLE   2,170 0 0
PINNACLE WEST CAP CORP COM 723484101 287 3,000 SH   SOLE   3,000 0 0
PNC FINCL SERVICES GROUP COM 693475105 900 7,335 SH   SOLE   7,335 0 0
POOL CORPORATION COM 73278l105 511 3,098 SH   SOLE   3,098 0 0
PRICE T ROWE GROUP INC COM 74144T108 12,356 123,415 SH   SOLE   123,415 0 0
PROCTER & GAMBLE CO COM 742718109 15,242 146,488 SH   SOLE   146,488 0 0
PROS HOLDINGS INC COM 74346Y103 119,978 2,840,379 SH   SOLE   2,840,379 0 0
QUALCOMM INC COM 747525103 20,175 353,767 SH   SOLE   353,767 0 0
QUALYS INC COM COM 74758t303 51,138 618,062 SH   SOLE   618,062 0 0
REALTY INCM CRP MD PV$1.REIT COM 756109104 208 2,832 SH   SOLE   2,832 0 0
RED HAT INC COM 756577102 84,560 462,837 SH   SOLE   462,837 0 0
ROPER TECHNOLOGIES INC COM 776696106 189,687 554,688 SH   SOLE   554,688 0 0
RPM INTERNATIONAL INC COM 749685103 249 4,285 SH   SOLE   4,285 0 0
S & P GLOBAL INC COM 78409V104 115,825 550,107 SH   SOLE   550,107 0 0
SALESFORCE.COM INC COM 79466L302 356 2,248 SH   SOLE   2,248 0 0
SBA COMMUNICATIONS CORP CL A COM 78410G104 64,066 320,875 SH   SOLE   320,875 0 0
SCHLUMBERGER LTD COM 806857108 2,953 67,767 SH   SOLE   67,767 0 0
SEI INVESTMENTS CO COM 784117103 73,276 1,402,412 SH   SOLE   1,402,412 0 0
SERVICE CORP INTL COM 817565104 261 6,500 SH   SOLE   6,500 0 0
SITEONE LANDSCAPE SUPPLY, INC. COM 82982L103 6,732 117,804 SH   SOLE   117,804 0 0
STANLEY BLACK & DECK COM 854502101 274 2,010 SH   SOLE   2,010 0 0
STERIS PLC COM G8473t100 813 6,351 SH   SOLE   6,351 0 0
STRYKER CORP COM 863667101 203 1,030 SH   SOLE   1,030 0 0
SYNCHRONY FINANCIAL COM 87165b103 206 6,458 SH   SOLE   6,458 0 0
TE CONNECTIVITY LTD F COM h84989104 2,072 25,659 SH   SOLE   25,659 0 0
TELADOC INC COM 87918A105 5,272 94,815 SH   SOLE   94,815 0 0
TELEFLEX INC COM COM 879369106 78,616 260,179 SH   SOLE   260,179 0 0
THE BOEING CO COM 097023105 337 884 SH   SOLE   884 0 0
THE DESCARTES SYSTEMS GROUP IN COM 249906108 2,405 66,108 SH   SOLE   66,108 0 0
THERMO FISHER SCNTFC COM 883556102 36,295 132,599 SH   SOLE   132,599 0 0
TRACTOR SUPPLY COMP COM 892356106 1,233 12,609 SH   SOLE   12,609 0 0
TRANSDIGM GROUP INC COM 893641100 122,136 269,027 SH   SOLE   269,027 0 0
TRANSUNION COM 89400j107 18,392 275,171 SH   SOLE   275,171 0 0
TRIMBLE INC COM 896239100 110,347 2,731,369 SH   SOLE   2,731,369 0 0
TRUPANION, INC. COM 898202106 3,762 114,916 SH   SOLE   114,916 0 0
TYLER TECHNOLOGIES INC COM 902252105 155,002 758,329 SH   SOLE   758,329 0 0
U S BANCORP COM 902973304 1,293 26,831 SH   SOLE   26,831 0 0
ULTIMATE SOFTWARE GROUP INC COM 90385D107 3,786 11,468 SH   SOLE   11,468 0 0
UNION PACIFIC CORP COM 907818108 349 2,090 SH   SOLE   2,090 0 0
UNITED PARCEL SERVICE INC CL B COM 911312106 329 2,941 SH   SOLE   2,941 0 0
UNITED TECHNOLOGIES CORP. COM 913017109 3,141 24,366 SH   SOLE   24,366 0 0
UNITEDHEALTH GRP INC COM 91324p102 1,720 6,958 SH   SOLE   6,958 0 0
VAPOTHERM INC COM 922107107 4,237 215,632 SH   SOLE   215,632 0 0
VENTAS INC REIT COM 92276f100 1,297 20,324 SH   SOLE   20,324 0 0
VERISK ANALYTICS INC COM 92345Y106 194,711 1,463,991 SH   SOLE   1,463,991 0 0
VERIZON COMMUNICATIONS INC COM 92343v104 784 13,266 SH   SOLE   13,266 0 0
VISA INC CL A COM 92826C839 197,212 1,262,642 SH   SOLE   1,262,642 0 0
VULCAN MATERIALS COM 929160109 77,799 657,089 SH   SOLE   657,089 0 0
W.P. CAREY INC. REIT COM 92936u109 399 5,095 SH   SOLE   5,095 0 0
WALMART STORES COM 931142103 433 4,441 SH   SOLE   4,441 0 0
WASTE CONNECTIONS INC COM 94106B101 145,571 1,643,201 SH   SOLE   1,643,201 0 0
WATSCO INC COM 942622200 18,091 126,322 SH   SOLE   126,322 0 0
WAYFAIR COM 94419L101 7,326 49,349 SH   SOLE   49,349 0 0
WD-40 COMPANY COM 929236107 2,795 16,494 SH   SOLE   16,494 0 0
WELLS FARGO & CO COM 949746101 203 4,211 SH   SOLE   4,211 0 0
WEYERHAEUSER CO COM 962166104 1,432 54,370 SH   SOLE   54,370 0 0
WSFS FINANCIAL CORP COM 929328102 4,236 109,730 SH   SOLE   109,730 0 0
BLACKROCK ENHANCED EQT DIV TR ETFS 09251A104 85 10,000 SH   SOLE   10,000 0 0
ISHARES CORE S&P 500 ETF ETFS 464287200 1,230 4,324 SH   SOLE   4,324 0 0
ISHARES CORE S&P MID CAP ETF ETFS 464287507 1,105 5,834 SH   SOLE   5,834 0 0
ISHARES CORE S&P SMALL CAP ETF ETFS 464287804 486 6,303 SH   SOLE   6,303 0 0
ISHARES MSCI EAFE ETF ETFS 464287465 877 13,523 SH   SOLE   13,523 0 0
ISHARES RUSSELL 2000 GROWTH IN ETFS 464287648 624 3,174 SH   SOLE   3,174 0 0
ISHARES TR MSCI EMG MKT ETF ETFS 464287234 215 5,000 SH   SOLE   5,000 0 0
VANGUARD DIVIDEND APPREC ETFS 921908844 1,210 11,034 SH   SOLE   11,034 0 0
VANGUARD FTSE ALL WORLD EX US ETFS 922042775 3,334 66,478 SH   SOLE   66,478 0 0
VANGUARD FTSE EMERGING MARK ET ETFS 922042858 971 22,843 SH   SOLE   22,843 0 0
VANGUARD HIGH DVD YIELD ETF ETFS 921946406 636 7,426 SH   SOLE   7,426 0 0
VANGUARD INDEX FDS FORMERLY VA ETFS 922908363 4,961 19,114 SH   SOLE   19,114 0 0
VANGUARD REIT ETF ETFS 922908553 1,010 11,626 SH   SOLE   11,626 0 0
VANGUARD TOTAL STK MKT ETF ETFS 922908769 378 2,615 SH   SOLE   2,615 0 0
WISDOMTREE TR INDIA ERNGS FD ETFS 97717W422 237 9,000 SH   SOLE   9,000 0 0