Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (loss)
Balance (in shares) at Dec. 31, 2018		13,968,852
Balance at Dec. 31, 2018	$ 46,386	$ 14	$ 70,451	$ (24,010)	$ (69)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee purchase plan (in shares)		82,810
Issuance of common stock for employee purchase plan	$ 1,281		1,281
Exercise of stock options (in shares)	160,798	160,798
Exercise of stock options	$ 1,613		1,613
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes (in shares)		103,126
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes	(831)		(831)
Stock-based compensation expense	9,832		9,832
Net income (loss)	(12,348)			(12,348)
Net change in unrealized gain on available-for-sale investments	9				9
Balance (in shares) at Dec. 31, 2019		14,315,586
Balance at Dec. 31, 2019	45,942	$ 14	82,346	(36,358)	(60)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee purchase plan (in shares)		56,751
Issuance of common stock for employee purchase plan	$ 632		632
Exercise of stock options (in shares)	73,227	73,227
Exercise of stock options	$ 947		947
Issuance of common stock in connection with public offering, net of issuance costs of $2,303 (in shares)		2,742,750
Issuance of common stock in connection with public offering, net of issuance costs of $2,303	26,495	$ 3	26,492
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes (in shares)		490,918
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes	(3,428)	$ 1	(3,429)
Stock-based compensation expense	10,109		10,109
Net income (loss)	(23,877)			(23,877)
Net change in unrealized gain on available-for-sale investments	$ 60				60
Balance (in shares) at Dec. 31, 2020	17,679,232	17,679,232
Balance at Dec. 31, 2020	$ 56,880	$ 18	117,097	(60,235)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee purchase plan (in shares)		59,635
Issuance of common stock for employee purchase plan	$ 1,184		1,184
Exercise of stock options (in shares)	71,798	71,798
Exercise of stock options	$ 1,581		1,581
Purchase of capped call	(16,134)		(16,134)
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes (in shares)		184,679
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes	(2,176)		(2,176)
Stock-based compensation expense	13,172		13,172
Net income (loss)	2,062			2,062
Net change in unrealized gain on available-for-sale investments	$ 0
Balance (in shares) at Dec. 31, 2021	17,995,344	17,995,344
Balance at Dec. 31, 2021	$ 56,569	$ 18	$ 114,724	$ (58,173)	$ 0