Stock-Based Compensation - Stock option activity (Details) - $ / shares	1 Months Ended	12 Months Ended
	May 31, 2014	Dec. 31, 2019
Shares Available for Grant
Additional shares reserved (in shares)	77,908	763,973
Options granted (in shares)		(696,874)
Options cancelled (in shares)		129,883
End of the period (in shares)		196,982
Number of options
Number of Shares, beginning of the period (in shares)		825,205
Stock option granted		696,874
Number of Shares, Options exercised (in shares)		(11,884)
Number of Shares, Options cancelled (in shares)		(129,883)
Number of Shares, end of the period (in shares)		1,380,312
Weighted average exercise price
Weighted-Average Exercise Price, beginning of the period (in dollars per share)		$ 12.15
Weighted-Average Exercise Price, Options granted (in dollars per share)		8.52
Weighted-Average Exercise Price, Options exercised (in dollars per share)		2.89
Weighted-Average Exercise Price, Options cancelled (in dollars per share)		11.67
Weighted-Average Exercise Price, end of the period (in dollars per share)		$ 10.06