Setting cursorline raises missing argument: ctermbg=

On startup, and when trying to set colorscheme within neovim, I see the following:

Error detected while processing function <SNR>56_set_highlight_colors[37]..<SNR>56_add_to_highlight_group:
line    1:
E417: missing argument: ctermbg=
Error detected while processing function <SNR>56_set_highlight_colors[38]..<SNR>56_add_to_highlight_group:
line    1:
E417: missing argument: ctermbg=
Press ENTER or type command to continue

Here's another similar issue

Relevant lines from my init.vim:

set termguicolors
colorscheme atelier-heath
set background=dark
set cursorline

Here's the output of nvim --version:

NVIM v0.2.0-1-g9956bee
Build type: RelWithDebInfo
Compilation: /usr/local/Homebrew/Library/Homebrew/shims/super/clang -Wconversion -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1 -O2 -g -DDISABLE_LOG -Wall -Wextra -pedantic -Wno-unused-parameter -Wstrict-prototypes -std=gnu99 -Wvla -fstack-protector-strong -fdiagnostics-color=auto -DINCLUDE_GENERATED_DECLARATIONS -DHAVE_CONFIG_H -I/tmp/neovim-20161128-90483-jsyzwd/build/config -I/tmp/neovim-20161128-90483-jsyzwd/src -I/usr/local/include -I/usr/local/include -I/usr/local/include -I/usr/local/include -I/usr/local/include -I/usr/local/opt/gettext/include -I/usr/include -I/usr/include -I/tmp/neovim-20161128-90483-jsyzwd/build/src/nvim/auto -I/tmp/neovim-20161128-90483-jsyzwd/build/include
Compiled by aaron@Aarons-MacBook-Pro.local

Optional features included (+) or not (-): +acl   +iconv    -jemalloc +tui
For differences from Vim, see :help vim-differences

   system vimrc file: "$VIM/sysinit.vim"
  fall-back for $VIM: "/usr/local/Cellar/neovim/HEAD-9956bee/share/nvim"

Soares / base16.nvim

Setting cursorline raises missing argument: ctermbg= #1