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 11,487 588,455 SH   SOLE   588,455 0 0
3M CO COM COM 88579Y101 662 4,289 SH   SOLE   4,289 0 0
AAC HLDGS INC COM COM 000307108 12,927 296,773 SH   SOLE   296,773 0 0
ABBOTT LABS COM COM 002824100 566 11,539 SH   SOLE   11,539 0 0
ABBVIE INC COM COM 00287Y109 595 8,855 SH   SOLE   8,855 0 0
ACTUANT CORP CL A NEW COM 00508X203 235 10,176 SH   SOLE   10,176 0 0
AFFILIATED MANAGERS GROUP COM COM 008252108 1,581 7,233 SH   SOLE   7,233 0 0
ALIGN TECHNOLOGY INC COM COM 016255101 1,283 20,464 SH   SOLE   20,464 0 0
ALTERA CORP COM COM 021441100 359 7,018 SH   SOLE   7,018 0 0
AMAZON COM INC COM COM 023135106 392 903 SH   SOLE   903 0 0
AMBER RD INC COM COM 02318Y108 336 47,863 SH   SOLE   47,863 0 0
AMERICAN TOWER CORP NEW COM COM 03027X100 77,476 830,490 SH   SOLE   830,490 0 0
AMETEK INC NEW COM COM 031100100 1,000 18,254 SH   SOLE   18,254 0 0
AMPHENOL CORP NEW CL A COM 032095101 1,932 33,332 SH   SOLE   33,332 0 0
ANADARKO PETE CORP COM COM 032511107 414 5,300 SH   SOLE   5,300 0 0
ANSYS INC COM COM 03662Q105 175,685 1,925,529 SH   SOLE   1,925,529 0 0
APACHE CORP COM COM 037411105 242 4,203 SH   SOLE   4,203 0 0
APPLE INC COM COM 037833100 1,630 12,998 SH   SOLE   12,998 0 0
APPLIED MINERALS INC COM COM 03823M100 46 80,000 SH   SOLE   80,000 0 0
ATRION CORP COM COM 049904105 3,029 7,722 SH   SOLE   7,722 0 0
AUTOMATIC DATA PROCESSING INC COM 053015103 1,912 23,832 SH   SOLE   23,832 0 0
BARD C R INC COM COM 067383109 1,112 6,515 SH   SOLE   6,515 0 0
BEACON ROOFING SUPPLY INC COM COM 073685109 672 20,236 SH   SOLE   20,236 0 0
BECTON DICKINSON & CO COM COM 075887109 266 1,875 SH   SOLE   1,875 0 0
BERKLEY W R CORP COM COM 084423102 3,221 62,031 SH   SOLE   62,031 0 0
BERKSHIRE HATHAWAY INC DEL CL COM 084670108 1,434 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAY INC DEL CL COM 084670702 3,157 23,195 SH   SOLE   23,195 0 0
BIO TECHNE CORP COM COM 09073M104 15,894 161,413 SH   SOLE   161,413 0 0
BIOGEN INC COM COM 09062X103 59,526 147,364 SH   SOLE   147,364 0 0
BLACKBAUD INC COM COM 09227Q100 39,550 694,469 SH   SOLE   694,469 0 0
CAMPBELL SOUP CO COM COM 134429109 205 4,300 SH   SOLE   4,300 0 0
CANADIAN NATL RY CO COM COM 136375102 1,155 20,000 SH   SOLE   20,000 0 0
CAPELLA EDUCATION COMPANY COM COM 139594105 218 4,069 SH   SOLE   4,069 0 0
CAPITAL ONE FINL CORP COM COM 14040H105 2,278 25,898 SH   SOLE   25,898 0 0
CARMAX INC COM COM 143130102 85,701 1,294,385 SH   SOLE   1,294,385 0 0
CELGENE CORP COM COM 151020104 105,691 913,215 SH   SOLE   913,215 0 0
CERNER CORP COM COM 156782104 1,765 25,555 SH   SOLE   25,555 0 0
CHEVRON CORP NEW COM COM 166764100 963 9,984 SH   SOLE   9,984 0 0
CHIPOTLE MEXICAN GRILL INC COM COM 169656105 45,110 74,563 SH   SOLE   74,563 0 0
CHURCH & DWIGHT INC COM COM 171340102 1,356 16,714 SH   SOLE   16,714 0 0
CISCO SYS INC COM COM 17275R102 2,472 90,010 SH   SOLE   90,010 0 0
COCA COLA CO COM COM 191216100 1,107 28,214 SH   SOLE   28,214 0 0
COGNIZANT TECHNOLOGY SOLUTIONS COM 192446102 1,494 24,452 SH   SOLE   24,452 0 0
COLGATE PALMOLIVE CO COM COM 194162103 654 10,000 SH   SOLE   10,000 0 0
COMCAST CORP NEW CL A COM 20030N101 759 12,625 SH   SOLE   12,625 0 0
COMCAST CORP NEW CL A SPL COM 20030N200 4,132 68,934 SH   SOLE   68,934 0 0
CONCHO RES INC COM COM 20605P101 3,237 28,430 SH   SOLE   28,430 0 0
CORE LABORATORIES N V COM COM N22717107 3,267 28,649 SH   SOLE   28,649 0 0
COSTAR GROUP INC COM COM 22160N109 80,854 401,739 SH   SOLE   401,739 0 0
CROWN CASTLE INTL CORP NEW COM COM 22822V101 5,396 67,197 SH   SOLE   67,197 0 0
DEALERTRACK TECHNOLOGIES INC C COM 242309102 1,524 24,272 SH   SOLE   24,272 0 0
DENTSPLY INTL INC NEW COM COM 249030107 242 4,700 SH   SOLE   4,700 0 0
DISCOVER FINL SVCS COM COM 254709108 93,088 1,615,553 SH   SOLE   1,615,553 0 0
DISNEY WALT CO COM DISNEY COM 254687106 1,093 9,579 SH   SOLE   9,579 0 0
DONALDSON INC COM COM 257651109 914 25,535 SH   SOLE   25,535 0 0
DOUGLAS DYNAMICS INC COM COM 25960R105 834 38,809 SH   SOLE   38,809 0 0
DU PONT E I DE NEMOURS & CO CO COM 263534109 320 5,007 SH   SOLE   5,007 0 0
DUKE REALTY CORP COM NEW COM 264411505 274 14,750 SH   SOLE   14,750 0 0
EAST WEST BANCORP INC COM COM 27579R104 2,103 46,928 SH   SOLE   46,928 0 0
ECOLAB INC COM COM 278865100 113,484 1,003,663 SH   SOLE   1,003,663 0 0
ELLIE MAE INC COM COM 28849P100 3,955 56,674 SH   SOLE   56,674 0 0
EMERSON ELEC CO COM COM 291011104 510 9,209 SH   SOLE   9,209 0 0
ENTERPRISE PRODS PARTNERS L P COM 293792107 550 18,400 SH   SOLE   18,400 0 0
ENVESTNET INC COM COM 29404K106 886 21,913 SH   SOLE   21,913 0 0
EQT CORP COM COM 26884L109 3,218 39,560 SH   SOLE   39,560 0 0
EQUITY RESIDENTIAL SH BEN INT COM 29476L107 497 7,076 SH   SOLE   7,076 0 0
EXACT SCIENCES CORP COM COM 30063P105 559 18,800 SH   SOLE   18,800 0 0
EXAMWORKS GROUP INC COM COM 30066A105 68,364 1,748,433 SH   SOLE   1,748,433 0 0
EXPEDITORS INTL WASH INC COM COM 302130109 1,145 24,834 SH   SOLE   24,834 0 0
EXPONENT INC COM COM 30214U102 35,845 800,474 SH   SOLE   800,474 0 0
EXPRESS SCRIPTS HLDG CO COM COM 30219G108 1,794 20,176 SH   SOLE   20,176 0 0
EXXON MOBIL CORP COM COM 30231G102 1,803 21,667 SH   SOLE   21,667 0 0
FASTENAL CO COM COM 311900104 118,586 2,811,434 SH   SOLE   2,811,434 0 0
FINANCIAL ENGINES INC COM COM 317485100 60,675 1,428,331 SH   SOLE   1,428,331 0 0
FISERV INC COM COM 337738108 7,536 90,982 SH   SOLE   90,982 0 0
FORTINET INC COM COM 34959E109 1,274 30,830 SH   SOLE   30,830 0 0
FREEPORT-MCMORAN INC CL B COM 35671D857 234 12,576 SH   SOLE   12,576 0 0
GENERAL ELECTRIC CO COM COM 369604103 3,309 124,551 SH   SOLE   124,551 0 0
GENESEE & WYO INC CL A COM 371559105 971 12,750 SH   SOLE   12,750 0 0
GENUINE PARTS CO COM COM 372460105 362 4,044 SH   SOLE   4,044 0 0
GILEAD SCIENCES INC COM COM 375558103 898 7,667 SH   SOLE   7,667 0 0
GOOD TIMES RESTAURANTS INC COM COM 382140879 90 10,194 SH   SOLE   10,194 0 0
GOOGLE INC CL A COM 38259P508 253 469 SH   SOLE   469 0 0
GOOGLE INC CL C COM 38259P706 264 507 SH   SOLE   507 0 0
GUIDEWIRE SOFTWARE INC COM COM 40171V100 393 7,430 SH   SOLE   7,430 0 0
HCP INC COM COM 40414L109 3,706 101,623 SH   SOLE   101,623 0 0
HEALTH CARE REIT INC COM COM 42217K106 299 4,551 SH   SOLE   4,551 0 0
HEALTHCARE SVCS GRP INC COM COM 421906108 81,882 2,477,506 SH   SOLE   2,477,506 0 0
HOME DEPOT INC COM COM 437076102 353 3,178 SH   SOLE   3,178 0 0
HUNT J B TRANS SVCS INC COM COM 445658107 853 10,395 SH   SOLE   10,395 0 0
IDEXX LABS INC COM COM 45168D104 8,079 125,956 SH   SOLE   125,956 0 0
IHS INC CL A COM 451734107 1,379 10,719 SH   SOLE   10,719 0 0
II VI INC COM COM 902104108 222 11,686 SH   SOLE   11,686 0 0
ILLINOIS TOOL WKS INC COM COM 452308109 220 2,400 SH   SOLE   2,400 0 0
ILLUMINA INC COM COM 452327109 21,739 99,554 SH   SOLE   99,554 0 0
IMAX CORP COM COM 45245E109 104,811 2,602,704 SH   SOLE   2,602,704 0 0
INTEL CORP COM COM 458140100 13,412 440,979 SH   SOLE   440,979 0 0
INTERCONTINENTAL EXCHANGE INC COM 45866F104 1,430 6,396 SH   SOLE   6,396 0 0
INTERNATIONAL BUSINESS MACHS C COM 459200101 1,795 11,033 SH   SOLE   11,033 0 0
INTUIT COM COM 461202103 1,719 17,054 SH   SOLE   17,054 0 0
INTUITIVE SURGICAL INC COM NEW COM 46120E602 78,031 161,055 SH   SOLE   161,055 0 0
INVENTURE FOODS INC COM COM 461212102 258 25,412 SH   SOLE   25,412 0 0
IRON MTN INC NEW COM COM 46284V101 336 10,832 SH   SOLE   10,832 0 0
JACOBS ENGR GROUP INC DEL COM COM 469814107 367 9,047 SH   SOLE   9,047 0 0
JOHNSON & JOHNSON COM COM 478160104 10,304 105,726 SH   SOLE   105,726 0 0
JPMORGAN CHASE & CO COM COM 46625H100 362 5,341 SH   SOLE   5,341 0 0
LABORATORY CORP AMER HLDGS COM COM 50540R409 2,225 18,353 SH   SOLE   18,353 0 0
LILLY ELI & CO COM COM 532457108 816 9,776 SH   SOLE   9,776 0 0
LINCOLN NATL CORP IND COM COM 534187109 328 5,536 SH   SOLE   5,536 0 0
LKQ CORP COM COM 501889208 158,777 5,249,692 SH   SOLE   5,249,692 0 0
LOWES COS INC COM COM 548661107 202 3,022 SH   SOLE   3,022 0 0
LYNAS CORPORATION LTD SHS COM Q5683J103 2 75,000 SH   SOLE   75,000 0 0
M & T BK CORP COM COM 55261F104 434 3,474 SH   SOLE   3,474 0 0
MACYS INC COM COM 55616P104 315 4,663 SH   SOLE   4,663 0 0
MAGELLAN MIDSTREAM PRTNRS LP C COM 559080106 264 3,600 SH   SOLE   3,600 0 0
MARKEL CORP COM COM 570535104 129,275 161,457 SH   SOLE   161,457 0 0
MASTERCARD INC CL A COM 57636Q104 45,980 491,870 SH   SOLE   491,870 0 0
MCCORMICK & CO INC COM NON VTG COM 579780206 971 12,000 SH   SOLE   12,000 0 0
MCGRAW HILL FINL INC COM COM 580645109 47,762 475,478 SH   SOLE   475,478 0 0
MERCK & CO INC NEW COM COM 58933Y105 1,284 22,559 SH   SOLE   22,559 0 0
MICROSOFT CORP COM COM 594918104 2,705 61,268 SH   SOLE   61,268 0 0
MIDDLEBY CORP COM COM 596278101 2,968 26,445 SH   SOLE   26,445 0 0
MONRO MUFFLER BRAKE INC COM COM 610236101 805 12,952 SH   SOLE   12,952 0 0
MONSANTO CO NEW COM COM 61166W101 436 4,093 SH   SOLE   4,093 0 0
MOODYS CORP COM COM 615369105 125,038 1,158,190 SH   SOLE   1,158,190 0 0
NATIONAL AMERN UNIV HLDGS INC COM 63245Q105 44 15,000 SH   SOLE   15,000 0 0
NEOGEN CORP COM COM 640491106 465 9,800 SH   SOLE   9,800 0 0
O REILLY AUTOMOTIVE INC NEW CO COM 67103H107 19,346 85,611 SH   SOLE   85,611 0 0
ONEBEACON INSURANCE GROUP LTD COM G67742109 525 36,211 SH   SOLE   36,211 0 0
OXYSURE SYSTEMS INC COM COM 69208T101 6 10,000 SH   SOLE   10,000 0 0
PALL CORP COM COM 696429307 1,245 10,002 SH   SOLE   10,002 0 0
PANERA BREAD CO CL A COM 69840W108 3,731 21,350 SH   SOLE   21,350 0 0
PAYCHEX INC COM COM 704326107 3,169 67,601 SH   SOLE   67,601 0 0
PEPSICO INC COM COM 713448108 382 4,095 SH   SOLE   4,095 0 0
PERFORMANCE SPORTS GROUP LTD C COM 71377G100 506 28,100 SH   SOLE   28,100 0 0
PFIZER INC COM COM 717081103 1,170 34,895 SH   SOLE   34,895 0 0
PHILIP MORRIS INTL INC COM COM 718172109 430 5,362 SH   SOLE   5,362 0 0
PINNACLE WEST CAP CORP COM COM 723484101 279 4,900 SH   SOLE   4,900 0 0
PNC FINL SVCS GROUP INC COM COM 693475105 2,545 26,612 SH   SOLE   26,612 0 0
POLARIS INDS INC COM COM 731068102 1,522 10,276 SH   SOLE   10,276 0 0
POOL CORPORATION COM COM 73278L105 233 3,313 SH   SOLE   3,313 0 0
POTASH CORP SASK INC COM COM 73755L107 22,812 736,583 SH   SOLE   736,583 0 0
PRA GROUP INC COM COM 69354N106 106,484 1,708,934 SH   SOLE   1,708,934 0 0
PRECISION CASTPARTS CORP COM COM 740189105 360 1,800 SH   SOLE   1,800 0 0
PRICE T ROWE GROUP INC COM COM 74144T108 13,391 172,275 SH   SOLE   172,275 0 0
PRICESMART INC COM COM 741511109 3,040 33,317 SH   SOLE   33,317 0 0
PROCTER & GAMBLE CO COM COM 742718109 19,657 251,239 SH   SOLE   251,239 0 0
QUALCOMM INC COM COM 747525103 89,473 1,428,603 SH   SOLE   1,428,603 0 0
QUALYS INC COM COM 74758T303 9,498 235,387 SH   SOLE   235,387 0 0
RANGE RES CORP COM COM 75281A109 18,482 374,279 SH   SOLE   374,279 0 0
RED HAT INC COM COM 756577102 147,511 1,942,728 SH   SOLE   1,942,728 0 0
RESMED INC COM COM 761152107 677 12,005 SH   SOLE   12,005 0 0
ROPER TECHNOLOGIES INC COM COM 776696106 95,682 554,805 SH   SOLE   554,805 0 0
RPM INTL INC COM COM 749685103 201 4,100 SH   SOLE   4,100 0 0
SBA COMMUNICATIONS CORP COM COM 78388J106 1,692 14,715 SH   SOLE   14,715 0 0
SCHLUMBERGER LTD COM COM 806857108 22,384 259,701 SH   SOLE   259,701 0 0
SEI INVESTMENTS CO COM COM 784117103 165,119 3,367,710 SH   SOLE   3,367,710 0 0
SIGNATURE BK NEW YORK N Y COM COM 82669G104 1,631 11,140 SH   SOLE   11,140 0 0
SIGNET JEWELERS LIMITED SHS COM G81276100 106,068 827,105 SH   SOLE   827,105 0 0
SILVER WHEATON CORP COM COM 828336107 260 15,000 SH   SOLE   15,000 0 0
SMITH & NEPHEW PLC SPDN ADR NE COM 83175M205 255 7,500 SH   SOLE   7,500 0 0
SOTHERLY HOTELS INC COM COM 83600C103 96 13,625 SH   SOLE   13,625 0 0
SOUTHWESTERN ENERGY CO COM COM 845467109 318 13,975 SH   SOLE   13,975 0 0
STERICYCLE INC COM COM 858912108 105,622 788,751 SH   SOLE   788,751 0 0
STRATASYS LTD SHS COM M85548101 777 22,231 SH   SOLE   22,231 0 0
TANGOE INC COM COM 87582Y108 43,557 3,462,387 SH   SOLE   3,462,387 0 0
TESLA MTRS INC COM COM 88160R101 266 993 SH   SOLE   993 0 0
TEVA PHARMACEUTICAL INDS LTD A COM 881624209 307 5,197 SH   SOLE   5,197 0 0
TRACTOR SUPPLY CO COM COM 892356106 2,250 25,014 SH   SOLE   25,014 0 0
TRANSDIGM GROUP INC COM COM 893641100 15,723 69,981 SH   SOLE   69,981 0 0
TRIMBLE NAVIGATION LTD COM COM 896239100 70,746 3,015,619 SH   SOLE   3,015,619 0 0
TYLER TECHNOLOGIES INC COM COM 902252105 53,741 415,373 SH   SOLE   415,373 0 0
ULTIMATE SOFTWARE GROUP INC CO COM 90385D107 294 1,787 SH   SOLE   1,787 0 0
UNDER ARMOUR INC CL A COM 904311107 2,343 28,080 SH   SOLE   28,080 0 0
UNION PAC CORP COM COM 907818108 234 2,450 SH   SOLE   2,450 0 0
UNIT CORP COM COM 909218109 215 7,938 SH   SOLE   7,938 0 0
UNITED PARCEL SERVICE INC CL B COM 911312106 215 2,217 SH   SOLE   2,217 0 0
UNITED TECHNOLOGIES CORP COM COM 913017109 482 4,343 SH   SOLE   4,343 0 0
US BANCORP DEL COM NEW COM 902973304 1,236 28,486 SH   SOLE   28,486 0 0
V F CORP COM COM 918204108 279 4,000 SH   SOLE   4,000 0 0
VENTAS INC COM COM 92276F100 2,304 37,106 SH   SOLE   37,106 0 0
VERISK ANALYTICS INC CL A COM 92345Y106 102,958 1,415,036 SH   SOLE   1,415,036 0 0
VERIZON COMMUNICATIONS INC COM COM 92343V104 209 4,474 SH   SOLE   4,474 0 0
VISA INC COM CL A COM 92826C839 113,691 1,693,087 SH   SOLE   1,693,087 0 0
W P CAREY INC COM COM 92936U109 258 4,379 SH   SOLE   4,379 0 0
WABTEC CORP COM COM 929740108 1,542 16,358 SH   SOLE   16,358 0 0
WAGEWORKS INC COM COM 930427109 88,474 2,187,252 SH   SOLE   2,187,252 0 0
WASTE CONNECTIONS INC COM COM 941053100 76,013 1,613,179 SH   SOLE   1,613,179 0 0
WATSCO INC COM COM 942622200 817 6,600 SH   SOLE   6,600 0 0
WELLS FARGO & CO NEW COM COM 949746101 344 6,120 SH   SOLE   6,120 0 0
WHOLE FOODS MKT INC COM COM 966837106 623 15,800 SH   SOLE   15,800 0 0
WSFS FINL CORP COM COM 929328102 656 23,984 SH   SOLE   23,984 0 0
XOOM CORP COM COM 98419Q101 1,767 83,936 SH   SOLE   83,936 0 0
ZOES KITCHEN INC COM COM 98979J109 441 10,783 SH   SOLE   10,783 0 0
ISHARES TR MSCI EAFE ETF ETFS 464287465 213 3,347 SH   SOLE   3,347 0 0
VANGUARD INDEX FDS REIT ETF ETFS 922908553 422 5,655 SH   SOLE   5,655 0 0
VANGUARD INTL EQUITY INDEX FD ETFS 922042775 2,956 60,881 SH   SOLE   60,881 0 0
VANGUARD INTL EQUITY INDEX FD ETFS 922042858 528 12,925 SH   SOLE   12,925 0 0
VANGUARD SPECIALIZED PORTFOLIO ETFS 921908844 955 12,150 SH   SOLE   12,150 0 0
VANGUARD WHITEHALL FDS INC HIG ETFS 921946406 349 5,185 SH   SOLE   5,185 0 0