Consolidated Statements of Changes In Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (loss)
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)		39,248
Issuance of common stock for employee purchase plan	437		437
Exercise of stock options (in shares)		46,878
Exercise of stock options	419		419
Issuance of common stock in settlement of restricted and performance stock unites, net of shares withheld for employee taxes (in shares)		481,387
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes	(3,340)	$ 1	(3,341)
Issuance of common stock in connection with public offering, net of offering cost of $2,303 (in shares)		2,742,750
Issuance of common stock in connection with public offering, net of offering cost of $2,303	26,495	$ 3	26,492
Stock-based compensation expense	8,057		8,057
Net income (loss)	(26,065)			(26,065)
Net change in unrealized loss on available-for-sale investments	61				61
Balance (in shares) at Sep. 30, 2020		17,625,849
Balance at Sep. 30, 2020	52,006	$ 18	114,410	(62,423)	1
Balance (in shares) at Jun. 30, 2020		17,567,688
Balance at Jun. 30, 2020	52,499	$ 18	112,644	(60,166)	3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		750
Exercise of stock options	8		8
Issuance of common stock in settlement of restricted and performance stock unites, net of shares withheld for employee taxes (in shares)		57,411
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes	(224)	$ 0	(224)
Stock-based compensation expense	1,982		1,982
Net income (loss)	(2,257)			(2,257)
Net change in unrealized loss on available-for-sale investments	(2)				(2)
Balance (in shares) at Sep. 30, 2020		17,625,849
Balance at Sep. 30, 2020	$ 52,006	$ 18	114,410	(62,423)	1
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)		38,991
Issuance of common stock for employee purchase plan	$ 648		648
Exercise of stock options (in shares)	57,498	57,498
Exercise of stock options	$ 1,408		1,408
Purchase of capped call	(16,134)		(16,134)
Issuance of common stock in settlement of restricted and performance stock unites, net of shares withheld for employee taxes (in shares)		175,813
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes	(1,963)		(1,963)
Stock-based compensation expense	8,507		8,507
Net income (loss)	5,997			5,997
Net change in unrealized loss on available-for-sale investments	$ 0
Balance (in shares) at Sep. 30, 2021	17,951,534	17,951,534
Balance at Sep. 30, 2021	$ 55,343	$ 18	109,563	(54,238)	0
Balance (in shares) at Jun. 30, 2021		17,933,020
Balance at Jun. 30, 2021	53,343	$ 18	106,173	(52,848)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee purchase plan (in shares)		0
Issuance of common stock for employee purchase plan	3		3
Exercise of stock options (in shares)		3,900
Exercise of stock options	156		156
Issuance of common stock in settlement of restricted and performance stock unites, net of shares withheld for employee taxes (in shares)		14,614
Issuance of common stock in settlement of restricted and performance stock units, net of shares withheld for employee taxes	(511)		(511)
Stock-based compensation expense	3,742		3,742
Net income (loss)	(1,390)			(1,390)
Net change in unrealized loss on available-for-sale investments	$ 0
Balance (in shares) at Sep. 30, 2021	17,951,534	17,951,534
Balance at Sep. 30, 2021	$ 55,343	$ 18	$ 109,563	$ (54,238)	$ 0